<Page>

[Adaptec Letterhead]

                                                                    EXHIBIT 2.13



Thomas J. Shea
Senior Vice President and Chief Operating Officer
Roxio, Inc.
460 South Milpitas Boulevard
Milpitas, CA 95131

Dear Tom:

This letter of agreement ("Letter of Agreement") confirms the agreement of
Adaptec. Inc. ("Adaptec") and Roxio, Inc. ("Roxio") with respect to certain
Assigned Trademarks, with respect to certain Assigned Technology that is the
ReZoom product, and with respect to certain Assigned patents.

For the sum of $1.00, and other good and valuable consideration to be received
by Roxio in connection with the Separation, Roxio agrees as follows:

RECONVEYANCE OF CERTAIN ASSIGNED TECHNOLOGY

Effective immediately after Separation, Roxio hereby grants, reconveys and
assigns to Adaptec, by execution hereof (or, where appropriate or required, by
execution of separate instruments of assignment), all its right, title and
interest in and to the Assigned Technology that is or directly relates to the
ReZoom product including, without limitation, documentation and object code for
the ReZoom product and the source code files set forth on EXHIBIT A, to the
extent such Assigned Technology was conveyed to Roxio under the Master
Technology Ownership and License Agreement (the "Reconveyed Technology"), and
its Intellectual property Rights therein, to be held and enjoyed by Adaptec, its
successors and assigns. Roxio further covenants that Roxio will, without
demanding any further consideration therefor, at the request and expense of
Adaptec (except for the value of the time of Roxio employees), do all lawful and
just acts that may be or become necessary for evidencing, maintaining, recording
and perfecting Adaptec's rights to such Reconveyed Technology and its
Intellectual Property Rights therein, including but not limited to, execution
and acknowledgement of assignments and other instruments in a form reasonably
required by Adaptec for each Copyright and Database jurisdiction.


<Page>


RECONVEYANCE OF CERTAIN ASSIGNED TRADEMARKS

Effective immediately after Separation, Roxio hereby grants, reconveys and
assigns to Adaptec, by execution hereof (or, where appropriate or required, by
execution of separate instruments of assignment), all its right, title and
interest in and to the Assigned Trademarks set forth on EXHIBIT B (the
"Reconveyed Trademarks"), together with the goodwill of the business symbolized
by the Reconveyed Trademarks. Roxio further covenants that Roxio will, without
demanding any further consideration therefor, at the request and expense of
Adaptec (except for the value of the time of Roxio employees), do all lawful and
just acts that may be or become necessary for evidencing, maintaining, recording
and perfecting Adaptec's rights to such Reconveyed Trademarks, including but not
limited to, execution and acknowledgement of assignments and other instruments
in a form reasonably required by Adaptec for each Trademark jurisdiction.

RECONVEYANCE OF CERTAIN ASSIGNED PATENTS

Effective immediately after Separation, Roxio hereby grants, conveys and assigns
to Adaptec, by execution hereof (or, where appropriate or required, by execution
of separate instruments of assignment), all its right, title and interest in and
to the Assigned Patents set forth on EXHIBIT C ("Reconveyed Patents"), to be
held and enjoyed by Adaptec, its successors and assigns. Roxio further grants,
conveys and assigns to Adaptec all its right, title and interest in and to any
and all causes of action and rights of recovery for past infringement of the
Reconveyed Patents and the right to claim priority from the Reconveyed Patents.
Roxio will, without demanding any further consideration therefor, at the request
and expense of Adaptec (except for the value of the time of Roxio employees), do
all lawful and just acts, that may be or become necessary for prosecuting,
sustaining, and obtaining continuations, continuations-in-part and divisionals
of, or reissuing or re-examining, said Reconveyed Patents and for evidencing,
maintaining, recording and perfecting Adaptec's rights to said Reconveyed
Patents, including but not limited to execution and acknowledgement of
assignments and other instruments in a form reasonably required by Adaptec for
each Patent jurisdiction.

LICENSE TO ROXIO

Effective after Separation and immediately upon the grant, conveyance and
assignment of the Reconveyed Patents by Roxio to Adaptec, and in
consideration of the above agreements by Roxio, Adaptec hereby grants to
Roxio a nonexclusive, irrevocable, fully paid-up, worldwide license, without
the right to grant sublicenses except as described in this paragraph, under
the Reconveyed Patents to make (including the right to practice methods,
processes and procedures), have made, use, lease, sell, offer for sale and
import: (a) any products and services that are commercially released by Roxio
prior to or on the Separation Date that embody or are made in accordance with
any invention of the Reconveyed Patents ("Current Roxio Products"); and (b)
products or services containing functionality (i) embodied in a Current Roxio
Product, and (ii) embodying or made in accordance with any invention(s) of
the Reconveyed Patents, provided that this license shall not extend to any
functionality or feature of the product or service not embodied in a Current
Roxio Product. The licenses granted in this paragraph shall include the right
of Roxio to sublicense its Subsidiaries. Each sublicensed Subsidiary shall be
bound by the terms and conditions of the Master Patent

<Page>


Ownership and License Agreement as if it were named in the place of Roxio.
Any sublicense granted to a Subsidiary under the Reconveyed Patents shall
terminate on the date such Subsidiary ceases to be a Subsidiary.

CERTAIN DEFINITIONS

Capitalized terms in this Letter of Agreement, which are not otherwise defined,
shall have the meaning set forth in the Master Separation and Distribution
Agreement, Master Technology Ownership and License Agreement and the Master
Patent Ownership and License Agreement.

If the foregoing correctly reflects your understanding, please execute this
Letter of Agreement where provided below.

Sincerely,

ADAPTEC, INC.

/s/ Robert N. Stephens
- ----------------------



AGREED AND ACKNOWLEDGED:

ROXIO, INC.

By: /s/ Thomas J. Shea
    ------------------
    Thomas J. Shea