Exhibit 99.1

     ADIC Expects Third Quarter Revenue of $108 -- $110 Million;
           One Million Shares Repurchased During the Period

    REDMOND, Wash.--(BUSINESS WIRE)--Aug. 2, 2004--Advanced Digital
Information Corporation (Nasdaq:ADIC) today indicated that revenue for
the third quarter ending July 31, 2004 is likely to be between $108
and $110 million compared to $108 million in the same quarter last
year and $111 million reported in the preceding second quarter.
    Chairman and Chief Executive Officer Peter van Oppen noted,
"Although not finished closing the accounts, we believe final sales
results for the third quarter ended Saturday will be similar to both
the same quarter last year and the second quarter this year as
anticipated. Based on normal fourth quarter seasonal trends,
additional reseller strength and acceptance of new products, we expect
our full-year fiscal 2004 sales to grow at a rate in the high single
digits."
    ADIC noted today's updated revenue guidance was issued as a result
of Chief Financial Officer Jon Gacek's participation in two investor
conferences this week prior to release of final third quarter results
next week. Both presentations, scheduled August 3rd and 4th, will be
available via webcast. Details are available at www.adic.com/ir.
    Third quarter financial results are expected to be released after
market close on Thursday, August 12th. The conference call discussing
third quarter earnings and outlook will follow at 1:30 p.m. Pacific
Time (4:30 p.m. Eastern Time). A live webcast and replay of the call
will be available at the Company's website.
    Separately, ADIC noted that, pursuant to a previously announced
stock buy back program, it had repurchased just over one million
shares during the third quarter at an average price of approximately
$9.38 per share.

    About ADIC

    Advanced Digital Information Corporation (Nasdaq:ADIC) is a
leading provider of Intelligent Storage(TM) solutions to the open
systems marketplace. ADIC is the world's largest supplier of automated
tape systems using the drive technologies most often employed for
backing up open system, client-server networks.(1) The Company's data
management software, storage networking appliances, and disk-to-tape
data protection solutions provide IT managers innovative tools for
storing, managing and protecting their most valuable digital assets in
a variety of disk and tape environments. ADIC storage products are
available through a worldwide sales force and a global network of
resellers and OEMs, including Cray, Dell, EMC, Fujitsu-Siemens, HP,
IBM and Sun. Further information about ADIC is available at
www.adic.com.

    (1) Market Share: Gartner Dataquest, Tape Automation Systems
Market Shares, 2003, F. Yale, April 2004. ADIC and Scalar are
registered trademarks and Intelligent Storage and iPlatform are
trademarks of Advanced Digital Information Corporation. All other
trade or service marks mentioned in this document should be considered
the property of their respective owners.

    This release contains forward-looking statements relating to the
Company's future products and services and future operating results
that are subject to risks and uncertainties that could cause actual
results to differ materially from those projected. The words "expect",
"anticipate", and similar expressions identify forward-looking
statements, but their absence does not mean that the statement is not
forward-looking. These statements are not guarantees of future
performance and are subject to certain risks, uncertainties and
assumptions that are difficult to predict. Factors that could affect
the Company's actual results include general economic trends, purchase
deferrals by customers, technical competition or obsolescence, supply
constraints, changes in market pricing and production problems.
Reference is made to the Company's Annual Report on Form 10-K for the
year ended October 31, 2003 for a more detailed description of factors
that could affect the Company's actual results. Readers are cautioned
not to place undue reliance on these forward-looking statements, which
speak only as of the date of this release. The Company undertakes no
obligation to update publicly any forward-looking statements to
reflect new information, events or circumstances after the date of
this release or to reflect the occurrence of unanticipated events.

    CONTACT: ADIC
             Jon Gacek, 425-881-8004
             or
             Stacie Timmermans, 425-881-8004