NOTE PURCHASE AGREEMENT


                                      Among


                               NOVA HOLDINGS, INC.


                    WELSH, CARSON, ANDERSON & STOWE VII, L.P.


                                       and


                    the other several purchasers named herein




                            Dated as of June 4, 1997








                                TABLE OF CONTENTS




                                                                                                               Page
                                                                                                               ----
                                                                                                           
I.       PURCHASE AND SALE OF NOTES, CLOSING DATES..............................................................  1

                  SECTION 1.01  Sale and Purchase of Notes
                    and Common Stock..............................................................................1
                  SECTION 1.02  Closing Dates...................................................................  1

II.      REPRESENTATIONS AND WARRANTIES OF THE CORPORATION......................................................  2

                  SECTION 2.01  Organization and Corporate Power................................................  2
                  SECTION 2.02  Authorization of Agreements, Etc................................................  2
                  SECTION 2.03  Validity........................................................................  3
                  SECTION 2.04  Governmental Approvals..........................................................  3
                  SECTION 2.05  Absence of Changes and Defaults.................................................  3
                  SECTION 2.06  Use of Proceeds.................................................................  3

III.     REPRESENTATIONS AND WARRANTIES OF THE PURCHASERS.......................................................  3

IV.      CONDITIONS TO THE OBLIGATIONS OF THE PURCHASERS........................................................  4

                  SECTION 4.01  Notice of Closing Date..........................................................  4
                  SECTION 4.02  Representations and Warranties
                    to Be True and Correct......................................................................  4
                  SECTION 4.03  Initial Closing Date............................................................  4
                  SECTION 4.04  Performance.....................................................................  5

V.       MISCELLANEOUS..........................................................................................  5

                  SECTION 5.01  Expenses, Etc...................................................................  5
                  SECTION 5.02  Amendment to Registration Rights
                    Agreement...................................................................................  5
                  SECTION 5.03  Survival of Agreements..........................................................  5
                  SECTION 5.04  Parties in Interest.............................................................  5
                  SECTION 5.05  Notices.........................................................................  6
                  SECTION 5.06  Counterparts....................................................................  6
                  SECTION 5.07  Governing Law...................................................................  6

TESTIMONIUM  .....................................................................................................7









                          INDEX TO EXHIBIT AND SCHEDULE




  Item            Description            Section Reference
  ----            -----------            -----------------
                                 
EXHIBIT A         Form of Note                1.01(a)

Schedule I        Names and Addresses
                   of Purchasers










                  NOTE PURCHASE AGREEMENT, dated as of June 4, 1997, between
NOVA HOLDINGS, INC., a Delaware corporation (the "Corporation"), WELSH, CARSON,
ANDERSON & STOWE VII, L.P., a Delaware limited partnership ("WCAS VII"), and the
other several purchasers named on Schedule I hereto (collectively, the
"Purchasers").

                  WHEREAS the Corporation wishes to be able to issue and sell,
and the Purchasers are willing to purchase, up to $10,000,000 aggregate
principal amount of the Company's 10% Senior Subordinated Notes Due June 1, 2004
(collectively, the "Notes"), all on the terms and subject to the conditions
hereinafter set forth;

                  NOW, THEREFORE, in consideration of the premises and the
mutual covenants herein contained, the parties hereto agree as follows:

                                       I.

                    PURCHASE AND SALE OF NOTES, CLOSING DATES

                  SECTION 1.01 Sale and Purchase of Notes and Common Stock.

                  Subject to the terms and conditions hereinafter set forth,
from time to time on or prior to August 31, 1997 (the "Termination Date") each
Purchaser severally agrees to purchase, on request by the Corporation as
hereinafter provided, Notes not exceeding in the aggregate the principal amount
of Notes set forth opposite such Purchaser's name on Schedule I hereto. The
Notes shall be substantially in the form of Exhibit A hereto. The purchase price
payable for Notes shall in each case be 99.96% of their principal amount.
Concurrently with each purchase of Notes pursuant hereto, the Corporation shall
issue to each Purchaser one share of the Corporation's Common Stock, par value
$0.01 per share ("Common Stock"), for each $25 principal amount of Notes
purchased by such Purchaser at a price of $.01 per share. On each Closing Date
(as hereinafter defined), the Corporation shall sell and deliver to each
Purchaser the Note, dated the applicable Closing Date, and the shares of Common
Stock which are to be purchased by such Purchaser on such Closing Date, and as
payment in full against delivery thereof, such Purchaser shall, subject to the
satisfaction of the conditions set forth in Article IV, pay to the Corporation,
by wire transfer of immediately available funds to an account designated by the
Corporation, the purchase price payable for such Note and Common Stock.

                  SECTION 1.02 Closing Dates. The Corporation shall give written
notice to the Purchasers of each requested purchase 



hereunder (each such purchase to be for not less than $1,000,000 in aggregate
principal amount of Notes) not less than 5 business days prior to the Closing
Date therefor (which shall not be later than August 31, 1997), specifying the
respective amounts to be purchased by each of them, such amounts to be
proportionate to the respective aggregate principal amounts of Notes set forth
opposite their respective names on Schedule I hereto. The closing of each sale
and purchase hereunder shall take place at the offices of Reboul, MacMurray,
Hewitt, Maynard & Kristol, 45 Rockefeller Plaza, New York, N.Y. 10111 at 2 p.m.,
New York time, on the specified date in the Corporation's notice, or at such
other date and time as may be mutually agreed upon between the Purchaser and the
Corporation (each such date and time of the closing being herein called a
"Closing Date").


                                       II.

                REPRESENTATIONS AND WARRANTIES OF THE CORPORATION

                  The Corporation represents and warrants to the Purchasers as
follows:

                  SECTION 2.01 Organization and Corporate Power. The Corporation
is a corporation duly incorporated, validly existing and in good standing under
the laws of the State of Delaware. The Corporation has the corporate power and
authority to own and hold its properties, to carry on its business as currently
conducted and to execute, deliver and perform this Agreement and the Notes and
to issue the shares of Common Stock to be issued pursuant hereto.

                  SECTION 2.02 Authorization of Agreements, Etc. The execution
and delivery by the Corporation of this Agreement and the Notes and the issuance
of the Common Stock and the performance by the Corporation of its respective
obligations hereunder and thereunder have been duly authorized by all requisite
corporate action and will not violate any provision of law, any order of any
court or other agency of government, the Certificate of Incorporation or By-laws
of the Corporation, or any provision of any indenture, agreement (including,
without limitation the Loan and Security Agreement dated as of June 4, 1997 (the
"Loan Agreement") among the Corporation, its subsidiaries, NationsBank of
Tennessee, NA (individually and as Agent) and First Tennessee Bank National
Association) or other instrument to which the Corporation or any subsidiary, or
any of the properties or assets of the Corporation or any subsidiary is bound,
or conflict with, result in a breach of or constitute (with due notice or lapse
of time or both) a default under any such indenture, agreement or other
instrument, or result in the creation or imposition of any lien, charge or
encumbrance of any nature whatsoever upon any of the properties or assets of the
Corporation or any subsidiary.

                                       2


                 SECTION 2.03 Validity. This Agreement has been duly executed
and delivered by the Corporation and constitutes the legal, valid and binding
obligation of the Corporation, enforceable against the Corporation in accordance
with its terms, subject, as to enforcement of remedies, to applicable
bankruptcy, insolvency, reorganization, moratorium and similar laws from time to
time in effect affecting the enforcement of creditors' rights generally and to
general principles of equity. The Notes, when executed and delivered by the
Corporation against payment therefor as provided in this Agreement, will
constitute legal, valid and binding obligations of the Corporation, enforceable
against the Corporation in accordance with their terms, subject, as to
enforcement of remedies, to applicable bankruptcy, insolvency, reorganization,
moratorium and similar laws from time to time in effect affecting the
enforcement of creditors' rights generally and to general principles of equity.
The shares of Common Stock, when issued and delivered by the Corporation against
payment therefor as provided in this Agreement will be validly issued, fully
paid and nonassessable.

                  SECTION 2.04 Governmental Approvals. Subject to the accuracy
of the representations and warranties of the Purchasers set forth in Article III
hereof, no registration or filing with, or consent or approval of, or other
action by, any Federal, state or other governmental agency or instrumentality is
or will be necessary for the valid execution, delivery and performance of this
Agreement and the Note or the sale of the Note.

                  SECTION 2.05 Absence of Changes and Defaults. No material
adverse change in the business, results of operations of financial condition of
the Corporation and its subsidiaries, taken as a whole, has occurred since the
date of this Agreement, and no event of default or event which (with the giving
of notice or lapse of time or both) would become an event of default under the
Loan Agreement has occurred and is continuing.

                  SECTION 2.06 Use of Proceeds. The Corporation will use the
proceeds from the sale of the Notes to finance a portion of the cost of
acquiring Horizon Health Systems, Inc., a Tennessee corporation, and for general
corporate purposes.


                                      III.

                REPRESENTATIONS AND WARRANTIES OF THE PURCHASERS

                  Each Purchaser represents and warrants to the Corporation that
such Purchaser will acquire the Notes and Common Stock to be purchased by it
from the Corporation hereunder for its own account for the purpose of investment
and not with a view to or for sale in connection with any distribution thereof.
Each Purchaser further represents that it understands that (i) the 

                                       3



Notes and Common Stock have not been registered under the Securities Act of 1933
(the "Securities Act") by reason of their issuance in transactions exempt from
the registration requirements of the Securities Act pursuant to Section 4(2)
thereof, (ii) the Notes and Common Stock must be held indefinitely unless a
subsequent disposition thereof is registered under the Securities Act or is
exempt from such registration, (iii) the Notes and Common Stock will bear a
legend to such effect, and (iv) the Corporation will make a notation on its
transfer books to such effect. Each Purchaser further represents and warrants
that it has requested, received and reviewed all information which it deems
relevant in making a decision to purchase the Notes and Common Stock being
purchased by it hereunder. Each Purchaser represents and warrants that it is an
"accredited investor" within the meaning of Rule 501(a) under the Securities Act
of 1933.


                                    IV.

                 CONDITIONS TO THE OBLIGATIONS OF THE PURCHASERS

                  The obligations of the Purchasers to purchase and pay for the
Notes and Common Stock to be purchased by them hereunder on any Closing Date
are, at their option, subject to the satisfaction, on or before such Closing
Date, of the following conditions:

                  SECTION 4.01 Notice of Closing Date. The Corporation shall
have given notice of such Closing Date in conformity with Section 1.02.

                  SECTION 4.02 Representations and Warranties to Be True and
Correct. The representations and warranties contained in Article II hereof shall
be true and correct on and as of such Closing Date with the same effect as
though such representations and warranties had been made on and as of such date.

                  SECTION 4.03 Initial Closing Date. In the case of the first
Closing Date:

                  (a) The Corporation shall have completed, or concurrently with
the initial purchase hereunder shall complete, the acquisition of all of the
shares of Horizon Health Systems, Inc.

                  (b) The Corporation and all other parties thereto shall have
executed and delivered the Loan Agreement.

                  (c) All other parties shall have executed and delivered the
Intercreditor Agreement dated as of June 4, 1997 among the Corporation, its
subsidiaries, NationsBank of Tennessee, 

                                       4



N.A., First Tennessee Bank National Association and the other parties thereto,
including the Purchasers.

                  (d) All corporate and other proceedings to be taken by the
Corporation and all consents needed to be obtained by the Corporation in
connection with the transactions contemplated hereby, including any consent of
the lenders under the Loan Agreement, shall have been taken or obtained by the
Corporation and all documents incident thereto shall be satisfactory in form and
substance to the Purchasers and their counsel.

                  SECTION 4.04 Performance. The Corporation shall have performed
and complied with all agreements and conditions contained herein required to be
performed or complied with by it prior to or at such Closing Date.


                                       V.

                                  MISCELLANEOUS

                  SECTION 5.01 Expenses, Etc. Each party hereto will pay its own
expenses in connection with the transactions contemplated by this Agreement,
whether or not such transactions shall be consummated, except that the
Corporation shall pay the fees and disbursements of Reboul, MacMurray, Hewitt,
Maynard & Kristol, counsel for the Purchasers.

                  SECTION 5.02 Amendment to Registration Rights Agreement. The
Registration Rights Agreement dated as of May 31, 1996 between the Corporation
and the other parties thereto is hereby amended to confirm that the Common Stock
to be acquired by the Purchasers pursuant hereto shall constitute "Restricted
Stock" for purposes of that Agreement.

                  SECTION 5.03 Survival of Agreements. All covenants,
agreements, representations and warranties made herein shall survive the
execution and delivery of this Agreement and each issuance, sale and delivery of
the Notes and Common Stock pursuant hereto.

                  SECTION 5.04 Parties in Interest. All covenants and agreements
contained in this Agreement by or on behalf of any of the parties hereto shall
bind and inure to the benefit of the respective successors and assigns of the
parties hereto whether so expressed or not.

                  SECTION 5.05 Notices. Any notice or other communications
required or permitted hereunder shall be deemed to be sufficient if contained in
a written instrument delivered in person or duly sent by first class certified
mail, postage prepaid, or by facsimile addressed to such party at the address or

                                       5



facsimile number set forth below or such other address or facsimile number as
may hereafter be designated in writing by the addressee to the addressor:

                    if to the Corporation, to it at 1620 Century Center 
         Parkway, Suite 109, Memphis, Tennessee, 38134, Facsimile No. 
         1-800-827-8987, Attention:  Chief Financial Officer; or

                  if to any Purchaser, to it at the address or facsimile number
         for such Purchaser appearing on Schedule I hereto;

or, in any case, at such other address or addresses or facsimile number as shall
have been furnished in writing by such party to the other party hereto. All such
notices, requests, consents and other communications shall be deemed to have
been received (a) in the case of personal delivery, on the date of such
delivery, (b) in the case of mailing, on the fifth business day following the
date of such mailing and (c) in the case of facsimile, when received.

                  SECTION 5.06 Counterparts. This Agreement may be executed in
several counterparts, each of which shall be deemed an original, but all of
which together shall constitute one and the same instrument.

                  SECTION 5.07 Governing Law. This Agreement shall be governed
by and construed in accordance with the laws of the State of New York.

                                       6




                  IN WITNESS WHEREOF, the Company and the Purchasers have
executed this Agreement as of the day and year first above written.


                         NOVA HOLDINGS, INC.



                         By   /s/ Andrew M. Paul
                           ---------------------------------------------

                               Title: Assistant Secretary

                         WELSH, CARSON, ANDERSON & STOWE VII, L.P.
                         By WCAS VII Partners, L.P.,
                            General Partner



                          By /s/ Laura VanBuren
                            --------------------------------------------
                               General Partner


                         WCAS HEALTHCARE PARTNERS, L.P.
                         By WCAS HP Partners,
                            General Partner



                          By               *
                            --------------------------------------------



                                           *
                            --------------------------------------------
                                    Patrick J. Welsh



                                           *
                            --------------------------------------------
                                    Russell L. Carson



                                           *
                            --------------------------------------------
                                    Bruce K. Anderson



                                   /s/ Andrew M. Paul
                            --------------------------------------------
                                     Andrew M. Paul


 
                                           *
                            --------------------------------------------
                                   Thomas E. McInerney




                                           *
                            --------------------------------------------
                                    James B. Hoover



                                           *
                            -------------------------------------------- 
                                  Robert A. Minicucci



                                           *
                            --------------------------------------------
                                   Anthony J. de Nicola



                                           *
                            ---------------------------------------------
                                    Paul B. Queally



                              *By /s/ Laura VanBuren
                                 ----------------------------------------
                                           Attorney-in-fact


                               /s/ Laura VanBuren
                            --------------------------------------------
                                      Laura VanBuren


                         DE CHARTER TRUST CO., as Trustee f/b/o
                           the IRA/Rollover of Richard H. Stowe


                              /s/ 
                            --------------------------------------------



                                                               EXHIBIT A
                                                               ---------




            THIS NOTE IS ISSUED WITH ORIGINAL ISSUE DISCOUNT ("OID")
            AS DEFINED BY SECTION 1273(a)(1) OF THE INTERNAL REVENUE
             CODE OF 1986, AS AMENDED.  THE FOLLOWING INFORMATION IS
           PROVIDED PURSUANT TO THE INFORMATION REPORTING REQUIREMENTS
                  SET FORTH IN TREASURY REGULATION 1.1275-3.

              THE ISSUE PRICE, THE AMOUNT OF OID, THE ISSUE DATE AND
            THE YIELD TO MATURITY OF THIS DEBT INSTRUMENT PER QUARTER
                MAY BE OBTAINED UPON REQUEST FROM THE COMPANY'S
               CHIEF FINANCIAL OFFICER AT THE OFFICE REFERRED TO
                  IN SECTION 11(a) (TELEPHONE 901-385-6813).

           THIS NOTE HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF
            1933, AS AMENDED, OR ANY STATE SECURITIES LAWS. NEITHER THE
            SECURITIES EVIDENCED HEREBY, NOR ANY INTEREST THEREIN, MAY BE
            OFFERED, SOLD, TRANSFERRED, ENCUMBERED OR OTHERWISE DISPOSED
              OF UNLESS EITHER (I) THERE IS AN EFFECTIVE REGISTRATION
          STATEMENT UNDER SAID ACT AND LAWS RELATING THERETO OR (II) THE
              COMPANY HAS RECEIVED AN OPINION OF COUNSEL, REASONABLY
             SATISFACTORY IN FORM AND SUBSTANCE TO THE COMPANY, STATING
                     THAT SUCH REGISTRATION IS NOT REQUIRED.

          PURSUANT TO THE TERMS OF THAT CERTAIN INTERCREDITOR AGREEMENT
                    DATED AS OF JUNE 4, 1997, AS AMENDED,
               BETWEEN SUBORDINATED LENDERS AND SENIOR LENDERS
              (EACH AS DEFINED IN THE INTERCREDITOR AGREEMENT),
                 THE PAYMENT OF THIS NOTE IS SUBORDINATE TO
             THE PAYMENT OF CLAIMS ON THE PART OF SENIOR LENDERS
               AGAINST NOVA HOLDINGS, INC. AND ITS SUBSIDIARIES
           TO THE EXTENT SET FORTH IN SUCH INTERCREDITOR AGREEMENT.

                            NOVA HOLDINGS, INC.

                       10% Senior Subordinated Note
                             Due June 1, 2004


Registered                                                  New York, New York
R-00__                                                     _____________, 1997
$_________________

            NOVA HOLDINGS, INC., a Delaware corporation (hereinafter called the 
"Company"), for value received, hereby promises to pay to [Name], or its 
registered assigns, the principal sum of _____DOLLARS ($ __________) on June 1, 
2004, and to pay interest (computed on the basis of a 360-day year consisting 
of twelve 30-day months) from the date hereof on the unpaid stated principal 
sum hereof (as increased pursuant to Section 2) at the rate of 10% per annum, 
payable quarterly in arrears on the first day of




March, June, September and December of each year (each said day being an 
"Interest Payment Date"), commencing on September 1, 1997, until the 
principal amount hereof shall have become due and payable, whether at 
maturity or by acceleration or otherwise, and thereafter at the rate of 12% 
per annum on any overdue principal amount and (to the extent permitted by 
applicable law) on any overdue interest until paid. To the extent and in the 
manner provided in Section 2, accrued interest hereon may be capitalized and 
added to the unpaid principal amount hereof on certain Interest Payment Dates.

     All payments of principal and interest on this Note shall be in such 
coin or currency of the United States of America as at the time of payment 
shall be legal tender for payment of public and private debts, and shall be 
made at the offices of the person deemed the holder hereof in accordance with 
Section 5 below.

     For purposes of this Note, "Business Day" shall mean any day other than 
a Saturday, Sunday or a legal holiday under the laws of the State of New York.

     1.   Notes. This Note is one of a duly authorized issue of Notes (herein 
called the "Notes") made or to be made by the Company in the original 
aggregate principal amount of $10,000,000, maturing on June 1, 2004 (subject 
to increase as provided in Section 2) and bearing interest payable at the 
same rate and on the same dates as the interest on the principal amount of 
this Note.

     2.   Capitalization of Interest. The amount of interest otherwise due 
and payable hereon on each of September 1, 1997, December 1, 1997, March 1, 
1998 and June 1, 1998 shall be capitalized and added to the unpaid principal 
sum of this Note on the date it would otherwise be so payable. The amount of 
interest otherwise payable hereon on each of September 1, 1998, December 1, 
1998, March 1, 1999, and June 1, 1999 may, in each case at the option of the 
Company by notice to the holder given on or prior to the applicable Interest 
Payment Date (but with the consent of the holder if an Event of Default, as 
defined in Section 13, shall have occurred and be continuing), be capitalized 
and added to the unpaid principal sum of this Note on the date it would 
otherwise be so payable. All amounts so capitalized shall (unless the 
principal hereof shall have become overdue, by acceleration or otherwise, in 
which event the overdue rate shall apply) bear interest at the rate of 10% 
per annum, payable quarterly in arrears on each ensuing Interest Payment Date 
as provided above, except on any Interest Payment Date on which such interest 
is again capitalized as herein provided. Not more than five Business Days 
after each Interest Payment Date on which unpaid interest hereon shall be 
capitalized as provided herein, the Company shall deliver to the holder of 
this Note a certificate executed by its chief financial officer setting forth

                                       2



the amount of interest so capitalized and the date on which such interest was 
added to the principal sum hereof and copies thereof shall be maintained in 
the register maintained pursuant to paragraph (a) of Section 11.

      3.   Transfer, Etc. of Notes. The Company shall keep at its office or 
agency maintained as provided in paragraph (a) of Section 11 a register in 
which the Company shall provide for the registration of Notes and for the 
registration of transfer and exchange of Notes. The holder of this Note may, 
at its option, and either in person or by duly authorized attorney, surrender 
the same for registration of transfer or exchange at the office or agency of 
the Company maintained as provided in paragraph (a) of Section 11, and, 
without expense to such holder (except for taxes or governmental charges 
imposed in connection therewith), receive in exchange therefor a Note or 
Notes each in such denomination or denominations as such holder may request, 
dated as of the date to which interest has been paid on the Note or Notes so 
surrendered for transfer or exchange, for the same aggregate principal sum as 
the then unpaid principal sum of the Note or Notes so surrendered for 
transfer or exchange, and registered in the name of such person or persons as 
may be designated by such holder; provided, however, that if such Notes are 
to be registered in a name other than that of the registered holder, the new 
registered holder shall execute and become a party to the Intercreditor 
Agreement referred to in Section 17 if such Agreement is still in effect.  
Every Note presented or surrendered for registration of transfer or exchange 
shall be duly endorsed, or shall be accompanied by a written instrument of 
transfer, satisfactory in form to the Company, duly executed by the holder of 
such Note or his attorney duly authorized in writing. Every Note so made and 
delivered in exchange for this Note shall in all other respects be in the 
same form and have the same terms as this Note. In connection therewith, the 
Company shall make a notation on the new Notes of the amount of any interest 
added to the principal thereof pursuant to Section 2. No transfer or exchange 
of any Note shall be valid unless made in the foregoing manner at such office 
or agency.

     4.   Loss, Theft, Destruction or Mutilation of Note. Upon receipt of 
evidence satisfactory to the Company of the loss, theft, destruction or 
mutilation of this Note, and, in the case of any such loss, theft or 
destruction, upon receipt of an affidavit of loss and indemnity from the 
holder hereof reasonably satisfactory to the Company, or, in the case of any 
such mutilation, upon surrender and cancellation of this Note, the Company 
will make and deliver, in lieu of this Note, a new Note of like tenor and 
unpaid principal amount and dated as of the date to which interest has been 
paid on this Note.

     5.   Persons Deemed Owners; Holders. The Company may deem and treat the 
person in whose name any Note is registered as the owner and holder of such 
Note for the purpose of receiving


                                        3



payment of principal of and interest on such Note and for all other purposes 
whatsoever, whether or not such Note shall be overdue. With respect to any 
Note at any time outstanding, the term "holder", as used herein, shall be 
deemed to mean the person in whose name such Note is registered as aforesaid 
at such time.

    6.   Prepayments.   Subject to the provisions of the Intercreditor 
Agreement:

         (a)  Optional Prepayment.  Upon notice given as provided in Section 
     7 the Company may, at its option, prepay all or any portion of the 
     Notes, at the principal amount thereof so to be prepaid, together with 
     interest accrued thereon to the date fixed for such prepayment.

         (b)  Mandatory Prepayment.

         (i)  Public Offering.  If at any time while any of the Notes shall 
     be outstanding, the Company shall consummate a public offering of equity 
     securities of the Company pursuant to an effective registration 
     statement filed under the Securities Act of 1933, then the Company shall 
     use the net proceeds of such offering to prepay the principal amount of 
     the Notes (to the extent thereof), plus interest accrued thereon through 
     the date of prepayment.

         (ii) Sale of the Company.  If at any time while any of the Notes 
     shall be outstanding, (x) the Company shall merge or consolidate with or 
     into any other entity (other than a merger or consolidation in which (A) 
     at least 50% of the voting capital stock of the Company (or the 
     surviving or resulting entity, if other than the Company) outstanding 
     immediately after the effective date of such merger is owned of record 
     or beneficially by persons who owned voting capital stock of the Company 
     immediately prior to such merger or consolidation and in substantially 
     the same proportions in which such stock was held immediately prior to 
     such merger or consolidation, and (B) no Event of Default shall have 
     occurred as a result of the consummation thereof), or (y) the Company 
     shall sell, lease or otherwise dispose of all or substantially all of 
     its assets and properties as an entirety in a single transaction or in a 
     series of related transactions to an unaffiliated third party purchaser, 
     or (z) a majority of the outstanding capital stock of the Company shall 
     be acquired by an unaffiliated third party in a single transaction or 
     series of related transactions (any transaction described in clauses 
     (x), (y) or (z) above being referred to herein as a "Sale of the 
     Company"), then the Company shall take such action as may be necessary, 
     as a condition precedent to consummating


                                       4



          such Sale of the Company, to obtain all necessary waivers and
          consent (including the prepayments constituting "Permitted Payments"
          under the Intercreditor Agreement as defined in Section 17) and to
          provide funds sufficient to prepay, and shall prepay, 100% of the
          principal amount of the Notes, plus interest accrued thereon through
          the date of prepayment.

              (iii)   Prepayment to Avoid High-Yield OID. On any Interest
          Payment Date on or after June 1, 2002, the Company shall pay an
          amount of accrued original issue discount on any Note as shall be
          necessary to ensure that such Note shall not be considered an
          "applicable high yield discount obligation" within the meaning of
          Section 163(i) of the Internal Revenue Code of 1986, as amended, or
          any successor provision. The amount of principal payable on such Note
          shall be reduced by the amount of any accrued original issue discount
          that is paid under this Section 6(b).

     7.   Notice of Prepayment and Other Notices. The Company shall give
written notice of any prepayment of this Note or any portion hereof pursuant
to Section 6 not less than 10 nor more than 60 days prior to the date fixed
for such prepayment. Such notice of prepayment and all other notices to be
given to any holder of this Note shall be given by registered or certified
mail to the person in whose name this Note is registered at its address
designated on the register maintained by the Company on the date of mailing
such notice of prepayment or other notice. Upon notice of prepayment being
given as aforesaid, the Company covenants and agrees that it will prepay, on
the date therein fixed for prepayment, this Note or the portion hereof, as
the case may be, so called for prepayment, at the principal amount thereof so
called for prepayment together with interest accrued thereon to the date
fixed for such prepayment. Notwithstanding the foregoing, any notice of
prepayment pursuant to Section 6(b)(i) or (ii) may specify that the
obligation to make such prepayment is conditional upon the closing of the
transaction requiring such prepayment, in which event no prepayment shall be
required unless and until such transaction is consummated.

     8.   Allocation of Prepayment. In the event of any prepayment, purchase,
redemption or retirement of less than all of the outstanding Notes, the
Company will allocate the principal amount so to be prepaid, purchased,
redeemed or retired to each Note in proportion, as nearly as may be, to the
aggregate principal amount of all Notes then outstanding.

     9.   Interest After Date Fixed for Prepayment. If this Note or a portion
hereof is called for prepayment as herein provided, this Note or such portion
shall (unless the provisions of the last sentence of Section 7 become
applicable) cease to bear interest on and after the date fixed for such
prepayment unless,


                                       5




upon presentation for the purpose, the Company shall fail to pay this Note or 
such portion, as the case may be, in which event this Note or such portion, 
as the case may be, and, so far as may be lawful, any overdue installment of 
interest, shall bear interest on and after the date fixed for such 
prepayment and until paid at the rate per annum provided herein for overdue 
principal.

          10.  Surrender of Notes; Notation Thereon. Upon any prepayment of a 
portion of the principal amount of this Note, the holder hereof, at its 
option, may require the Company (subject to the provisions of the second 
sentence of Section 3) to execute and deliver at the expense of the Company 
(except for taxes or governmental charges imposed in connection therewith), 
upon surrender of this Note, a new Note registered in the name of such person 
or persons as may be designated by such holder for the principal amount of 
this Note then remaining unpaid, dated as of the date to which interest has 
been paid on the principal amount of this Note then remaining unpaid, or may 
present this Note to the Company for notation hereon of the payment of the 
portion of the principal amount of this Note so prepaid.

          11.  Covenants. The Company covenants and agrees that, so long as 
any Note shall be outstanding:

          (a)  Maintenance of Office. The Company will maintain an office or 
     agency in such place in the United States of America as the Company may 
     designate in writing to the registered holder hereof, where the Notes 
     may be presented for registration of transfer and exchange as herein 
     provided, where notices and demands to or upon the Company in respect of 
     the Notes may be served and where, at the option of the holders thereof, 
     the Notes may be presented for payment. Until the Company otherwise 
     notifies the holders of Notes, said office shall be the principal office 
     of the Company at 1620 Century Center Parkway, Suite 109, Memphis, 
     Tennessee, 38134.

          (b)  Payment of Taxes. The Company will promptly pay and discharge 
     or cause to be paid and discharged, before the same shall become in 
     default, all lawful taxes and assessments imposed upon the Company or 
     any subsidiary or upon the income and profits of the Company or any 
     subsidiary, or upon any property, real, personal or mixed, belonging to 
     the Company or any subsidiary, or upon any part thereof by the United 
     States or any State thereof, as well as all lawful claims for labor, 
     materials and supplies, which, if unpaid, would become a lien or charge 
     upon such property or any part thereof, provided, however, that neither 
     the Company nor any subsidiary shall be required to pay and discharge or 
     to cause to be paid and discharged any such tax, assessment, charge, 
     levy or claim so long as (i) the Company or a subsidiary shall be 
     contesting the validity thereof in good


                                       6




     faith or (ii) the Company shall, in its good faith judgment, deem the 
     validity thereof to be questionable and the party to whom such tax, 
     assessment, charge, levy or claim is allegedly owed shall not have made 
     written demand for the payment thereof.

          (c)  Corporate Existence. The Company will do or cause to be done 
     all things necessary and lawful to preserve and keep in full force and 
     effect its corporate existence, rights and franchises and the corporate 
     existence, rights and franchises of each of its subsidiaries; provided, 
     however, that nothing in this paragraph (c) shall prevent the 
     abandonment or termination of any rights or franchises of the Company, 
     or the liquidation or dissolution of, or a sale, transfer or disposition 
     (whether through merger, consolidation, sale or otherwise) of all or any 
     substantial part of the property and assets of, any subsidiary or the 
     abandonment or termination of the corporate existence, rights and 
     franchises of any subsidiary if such abandonment, termination, 
     liquidation, dissolution, sale, transfer or disposition is, in the good 
     faith business judgment of the Company, in the best interests of the 
     Company and is not disadvantageous in any material respect to the 
     holders of the Notes.

          (d)  Maintenance of Property. The Company will at all times maintain 
     and keep, or cause to be maintained and kept, in good repair, working 
     order and condition all significant properties of the Company and its 
     subsidiaries used in the conduct of the business of the Company and its 
     subsidiaries, and will from time to time make or cause to be made all 
     needful and proper repairs, renewals, replacements, betterments and 
     improvements thereto, so that the business carried on in connection 
     therewith may be properly and advantageously conducted at all times; 
     provided, however, that nothing in this paragraph (d) shall require (i) 
     the making of any repair or renewal or (ii) the continuance of the 
     operation and maintenance of any property or (iii) the retention of any 
     assets if such action (or inaction) is, in the good faith business 
     judgment of the Company, in the best interests of the Company (and the 
     best interests of any subsidiary concerned or affected thereby) and is 
     not disadvantageous in any material respect to the holders of the Notes.

          (e)  Insurance. The Company will, and will cause each of its 
     subsidiaries to, (i) keep adequately insured, by financially sound and 
     reputable insurers, all property of a character usually insured by 
     corporations engaged in the same or a similar business similarly 
     situated against loss or damage of the kinds customarily insured against 
     by such corporations and (ii) carry, with financially sound and 
     reputable insurers, such other insurance (including, without limitation, 
     liability insurance) in such amounts as are


                                       7



     available at reasonable expense and to the extent believed necessary in 
     the good faith business judgment of the Company.

          (f) Keeping of Books. The Company will at all times keep, and cause 
     each of its subsidiaries to keep, proper books of record and account in 
     which proper entries will be made of its transactions in accordance with 
     generally accepted accounting principles.

          (g) Notice of Default. If any one or more events which constitute, 
     or which with notice or lapse or time or both would constitute, an Event 
     of Default under Section 13 of this Note shall occur, or if the holder 
     of any Note shall demand payment or take any other action permitted upon 
     the occurrence of any such Event of Default, the Company shall, 
     immediately after it becomes aware that any such event has occurred or 
     that such demand has been made or that any such action has been taken, 
     give notice to all holders of the Notes, specifying the nature of such 
     event or of such demand or action, as the case may be; provided, however, 
     that if such event, in the good faith judgment of the Company, will be 
     cured within ten days after the Company has knowledge that such event 
     would, with or without notice or lapse of time or both, constitute 
     such an Event of Default, no such notice need be given if such Event of 
     Default shall be cured within such ten-day period.

          (h) Merger or Consolidation. If the Company shall effect a merger 
     or consolidation in which it is not the surviving entity and such 
     transaction is not a Sale of the Company under the provisions of Section 
     6(b)(ii) of this Note requiring mandatory prepayment of the Notes, then 
     the Company shall take such action as may be necessary, as a condition 
     to consummating such transaction, to cause the surviving entity to 
     assume all of the Company's obligations under the Notes, as if such 
     entity had been the original issuer thereof, and such entity shall 
     acknowledge in writing its obligation to fully and timely honor the 
     Company's obligations under the Notes.

     12. Modification by Holders; Waiver. The Company may, subject to the 
provisions of the Intercreditor Agreement (as defined in Section 17), with 
the written consent of the holders of not less than 66 2/3% in principal 
amount of the Notes then outstanding, modify the terms and provisions of the 
Notes or the rights of the holders of the Notes or the obligations of the 
Company thereunder, and the observance by the Company of any term or 
provision of the Notes may be waived with the written consent of the holders 
of not less than 66 2/3% in principal amount of 


                                    8



the Notes then outstanding; provided, however, that no such modification or 
waiver shall:

          (a)  change the maturity of any Note or reduce the principal amount 
     thereof or reduce the rate or extend the time of payment of interest 
     thereon without the consent of the holder of each Note so affected; or

          (b)  give any Note any preference over any other Note; or

          (c)  reduce the percentage of Notes, the consent of the holders of 
     which is required for any such modification; or

          (d)  amend the provisions of Section 17 hereof without the consent 
     of the holders of Senior Debt (as therein defined).

          Any such modification or waiver shall apply equally to all the 
holders of the Notes and shall be binding upon them, upon each future holder 
of any Note and upon the Company, whether or not such Note shall have been 
marked to indicate such modification or waiver, but any Note issued 
thereafter shall bear a notation referring to any such modification or 
waiver. Promptly after obtaining the written consent of the holders as herein 
provided, the Company shall transmit a Copy of such modification or waiver to 
all the holders of the Notes at the time outstanding.

          (13).   Events of Default.  If any one or more of the following 
events, herein called Events of Default shall occur, for any reason 
whatsoever, and whether such occurrence shall, on the part of the Company or 
any subsidiary, be voluntary or involuntary, result from compliance with the 
Intercreditor Agreement (as hereinafter defined) or come about or be effected 
by operation of law or pursuant to or in compliance with any judgement, 
decree or order of a court of competent jurisdiction or any order, rule or 
regulation of any administrative or other governmental authority, and such 
Event of Default shall be continuing:

          (a)  the Company shall not pay any principal of any Note when and 
     as the same shall become due and payable, whether at maturity or at a 
     date fixed for prepayment or by acceleration or otherwise; or

          (b)  the Company shall not pay any installment of interest on any 
     Note on any Interest Payment Date (unless capitalized pursuant to 
     Section 2), or shall not pay any interest when due in connection with 
     any prepayment or repayment of principal of any Note, and such 
     non-payment shall continue for a period of 10 Business Days; or


                                       9



          (c)  the Company shall fail to duly perform or observe any other 
     covenant, condition or agreement to be observed or performed by it 
     pursuant to the terms hereof and such failure shall continue for 30 days 
     after written notice thereof, specifying such failure and requesting 
     that the same be remedied, shall have been given to the Company by the 
     holder or holders of at least 25% of the principal amount of the Notes 
     then outstanding (the Company to give forthwith to all other holders of 
     Notes at the time outstanding written notice of the receipt of such 
     notice specifying the failure referred to therein); or

          (d)  any representation or warranty made by the Company in the Note 
     Purchase Agreement dated June 4, 1997 pursuant to which the Notes are 
     issued (taken singly or together with  other representations and 
     warranties made by the Company therein) shall prove to have been false 
     or incorrect on the date on or as of which made in any respect material 
     to the transactions contemplated by such Agreement; or 

          (e)  the entry of a decree or order for relief by a court having 
     jurisdiction in the premises in respect of the Company or any subsidiary 
     in an involuntary case under the federal bankruptcy laws, as now 
     constituted or hereafter amended, or any other applicable federal or 
     state bankruptcy, insolvency or other similar laws, or appointing a 
     receiver, liquidator, assignee, custodian, trustee, sequestrator (or 
     similar official) of the Company or any subsidiary or for any 
     substantial part of any of their property, or ordering the winding-up or 
     liquidation of any of their affairs and the continuance of any such 
     decree or order unstayed and in effect for a period of 60 consecutive 
     days; or

          (f)  the commencement by the Company or any subsidiary of a 
     voluntary case under the federal bankruptcy laws, as now constituted or 
     hereafter amended, or any other applicable federal or state bankruptcy, 
     insolvency or other similar laws, or the consent by any of them to the 
     appointment of or taking possession by a receiver, liquidator, assignee, 
     trustee, custodian, sequestrator (or other similar official) of the 
     Company or any subsidiary or for any substantial part of their property, 
     or the making by any of them of any assignment for the benefit of 
     creditors, or the failure of the Company or any subsidiary generally to 
     pay its debts as such debts become due; or

          (g)  default as defined in any instrument evidencing or under which 
     the Company or any subsidiary has outstanding at the time any 
     indebtedness for money borrowed in excess of $100,000 in aggregate 
     principal amount shall occur and as a result thereof the maturity of any 
     such indebtedness shall have been accelerated so that the same shall have 
     become due and payable prior to the date on which the same would other-


                                       10



     wise have become due and payable and such acceleration shall not have
     been rescinded or annulled within 30 days; or

          (h)  final judgment for the payment of money in excess of $100,000
     shall be rendered against the Company or a subsidiary and the same shall
     remain undischarged for a period of 30 days during which execution shall
     not be effectively stayed;

then, the holder or holders of a least 25% in aggregate principal amount of
the Notes at the time outstanding may, subject to the provisions of the
Intercreditor Agreement (as defined in Section 17) at its or their option, by 
notice to the Company, declare all the Notes to be, and all the Notes shall 
thereupon be and become, forthwith due and payable together with interest 
accrued thereon without presentment, demand, protest or further notice of any 
kind, all of which are expressly waived to the extent permitted by law.

    At any time after any declaration of acceleration as to all of the Notes 
has been made as provided in this Section 13, the holders of at least 66 2/3% 
in principal amount of the Notes then outstanding may, by notice to the 
Company, rescind such declaration and its consequences, if (i) the Company has
paid all overdue installments of interest on the Notes and all principal that 
has become due otherwise than by such declaration of acceleration and (ii) 
all other defaults and Events of Default (other than nonpayments of principal 
and interest that have become due solely by reason of acceleration) shall 
have been remedied or cured or shall have been waived pursuant to this 
paragraph; provided, however, that no such rescission shall extend to or 
affect any subsequent default or Event of Default or impair any right 
consequent thereon.

          14. Suits for Enforcement. In case any one or more of the Events of 
Default specified in Section 13 of this Note shall occur and be continuing, 
the holder of this Note may, subject to the provisions of the Intercreditor 
Agreement (as defined in Section 17) proceed to protect and enforce its 
rights by suit in equity, action at law and/or by other appropriate 
proceeding, whether for the specific performance of any covenant or agreement 
contained in this Note or in aid of the exercise of any power granted in this 
Note, or may proceed to enforce the payment of this Note or to enforce any 
other legal or equitable right of the holder of this Note.

          In case of any default under any Note, the Company will pay to the 
holder thereof such amounts as shall be sufficient to cover the reasonable 
costs and expenses of such holder due to said default, including, without 
limitation, collection costs and reasonable attorneys' fees, to the extent 
actually incurred.

          (15) Remedies Cumulative.  No remedy herein conferred upon the 
holder of this Note is intended to be exclusive of any


                                       11



other remedy and each and every such remedy shall be cumulative and shall be 
in addition to every other remedy given hereunder or now or hereafter 
existing at law or in equity or by statute or otherwise.

      16. Remedies Not Waived. No course of dealing between the Company and 
the holder of this Note or any delay on the part of the holder hereof in 
exercising any rights hereunder shall operate as a waiver of any right of any 
holder of this Note.

      17. Subordination and Intercreditor Agreement. (a) For purposes hereof, 
(i) the term "Intercreditor Agreement" means the Intercreditor Agreement 
dated as of June 4, 1997 among the Company, NationsBank of Tennessee, N.A., 
First Tennessee Bank National Association and the other parties thereto and 
(ii) the terms "Senior Debt" and "Senior Lenders" have the respective 
meanings given in the Intercreditor Agreement. Anything in this Note to the 
contrary notwithstanding, the obligation of the Company to pay the principal 
of and interest on this Note, and to discharge all its other obligations 
hereunder, shall be subordinate and junior in right of payment, to the extent 
set forth in the Intercreditor Agreement and the exercise of rights and 
remedies by the holder hereof are subject to the provisions thereof.

      (b) Subject to the payment in full of all Senior Debt, the holder of 
this Note shall be subrogated to the rights of the holders of Senior Debt to 
receive payments or distributions of any kind or character, whether in cash, 
property, stock or obligations, which may be payable or deliverable to the 
holders of Senior Debt, until the principal of, and interest on, this Note 
shall be paid in full, and, as between the Company, its creditors other than 
the holders of Senior Debt, and the holder of this Note, no such payment or 
distribution made to the holders of Senior Debt by virtue of the 
Intercreditor Agreement which otherwise would have been made to the holder of 
this Note shall be deemed a payment by the Company on account of the Senior 
Debt, it being understood that the provisions of this Section 17 and of the 
Intercreditor Agreement are and are intended solely for the purposes of 
defining the relative rights of the holder of this Note, on the one hand, and 
the holders of the Senior Debt, on the other hand. Subject to the rights of 
holders of Senior Debt to receive cash, property, stock or obligations 
otherwise payable or deliverable to the holder of this Note under the 
circumstances specified in the Intercreditor Agreement, nothing herein or in 
the Intercreditor Agreement shall, solely as between the Company and the 
holder of this Note, either impair the obligation of the Company, which is 
unconditional and absolute, to pay the holder hereof the principal hereof and 
interest hereon in accordance with the terms and provisions of this Note or, 
following any applicable Standstill Period (as defined in the Intercreditor 
Agreement), prevent the holder of this Note from exercising all remedies 
otherwise permitted by applicable law or upon default hereunder.


                                      12



          18.  Covenants Bind Successors and Assigns. All the covenants, 
stipulations, promises and agreements in this Note contained by or on behalf 
of the Company shall bind its successors and assigns, whether so expressed or 
not.

          19.  Governing Law. This Note shall be governed and construed in 
accordance with the laws of the State of New York.

          20.  Headings. The headings of the Sections and paragraphs of this 
Note are inserted for convenience only and do not constitute a part of this 
Note.


                                       13




          IN WITNESS WHEREOF, NOVA HOLDINGS, INC. has caused this Note to be 
signed in its corporate name by one of its officers thereunto duly authorized 
and to be dated as of the day and year first above written.


                                       NOVA HOLDINGS, INC.


                                       By:
                                           -------------------------------------
                                            Name:
                                           Title:




                                       14