THIS NOTE HAS NOT BEEN REGISTERED  UNDER THE SECURITIES ACT OF 1933 AND MAY NOT
BE SOLD,  TRANSFERRED  OR  ASSIGNED  UNLESS SO  REGISTERED  OR AN  EXEMPTIONFROM
REGISTRATION UNDER SAID ACT IS AVAILABLE.



                               IOMEGA CORPORATION

                       Senior Subordinated Promissory Note


$12,500,000                                                          Roy, Utah
                                                                  July 8, 1998


                              ---------------------

         Iomega Corporation,  a Delaware corporation (the "Company"),  for value
received,  hereby promises to pay to Idanta Partners,  or assigns, the principal
sum of $12,500,000 (Twelve Million Five Hundred Thousand Dollars), together with
interest  (computed on the basis of a 365-day  year) from the date hereof on the
unpaid  balance of such  principal  amount from time to time  outstanding at the
following rates:

        a.        from the date hereof  through  September 30, 1998, the greater
                  of (i) the  weighted-average  interest  rate charged under the
                  Credit  Agreement (as defined  below) at the beginning of such
                  period plus 2% per annum and (ii) 8.6875%;

         b.       from October 1, 1998 through December 31, 1998, the greater of
                  (i) the  weighted-average  interest  rate  charged  under  the
                  Credit  Agreement at the  beginning of such period plus 2% per
                  annum and (ii) 10.6875%; and

         c.       from January 1, 1999 until paid in full the greater of (i) the
                  weighted-average   interest  rate  charged  under  the  Credit
                  Agreement  at the  beginning  of such period plus 2% per annum
                  and (ii) 12.6875%.

All principal and interest shall be due and payable on March 31, 1999.

1.     Subordination.

     (a)  Subordination to Senior  Indebtedness.  The indebtedness  evidenced by
this Note, and the payment of the principal hereof,  and any interest hereon, is
wholly  subordinated,  junior and subject in right of payment, to the extent and
in  the  manner  hereinafter  provided,  to the  prior  payment  of  all  Senior
Indebtedness  of the Company now  outstanding  or  hereinafter  incurred  but is
senior to the Company's 6-3/4% Convertible  Subordinated Notes due 2001. "Senior
Indebtedness"  means  all  principal,  premium  (if any),  interest  (including,
without  limitation,  interest  accruing on or after,  or which would accrue but
for, the filing of any petition in bankruptcy or for reorganization  relating to
the  Company,  whether or not a claim for  post-petition  interest is allowed in
such  proceeding),  bank fees and other amounts  (including  attorneys' fees and
other costs of  collection)  owed by the Company with respect to the Amended and
Restated  Credit  Agreement And Collateral  Release dated as of January 23, 1998
among the Company,  the Banks named therein,  Citibank,  N.A., as Administrative
Agent,  and Morgan  Guaranty Trust Company of New York, as  Documentation  Agent
(the "Credit  Agreement"),  as the Credit  Agreement  may be amended or extended
from time to time, and any related documents.

     (b) (b1) No  Payment  if  Default  in Senior  Indebtedness.  No  payment on
account of  principal  of or interest on this Note shall be made,  and this Note
shall not be redeemed or purchased directly or indirectly by the Company (or any
of its subsidiaries),  if at the time of such payment or purchase or immediately
after giving effect thereto, (i) there shall exist a default in any payment with
respect to any Senior Indebtedness or (ii) there shall have occurred an event of
default  (other  than a default  in the  payment of amounts  due  thereon)  with
respect to any Senior Indebtedness, as defined in the instrument under which the
same is  outstanding,  permitting the holders thereof to accelerate the maturity
thereof,  and such event of default shall not have been cured or waived or shall
not have ceased to exist.

     (b2) No Payment if Loans Outstanding Under Senior Indebtedness.  Except for
payments permitted by Section 2 of this Note, no payment on account of principal
of or interest  on this Note shall be made,  and this Note shall not be redeemed
or purchased directly or indirectly by the Company (or any of its subsidiaries),
if at the time of such payment or purchase or  immediately  after giving  effect
thereto loans would be outstanding under the Credit Agreement.

     (c) Payment upon Dissolution, Etc.

     (i)In   the   event   of  any   bankruptcy,   insolvency,   reorganization,
receivership,  composition, assignment for benefit of creditors or other similar
proceeding  initiated by or against the Company or any dissolution or winding up
or  total  or  partial  liquidation  or  reorganization  of the  Company  (being
hereinafter  referred  to as a  "Proceeding"),  all claims of the holder of this
Note with respect to this Note in such Proceeding shall be deemed assigned,  pro
rata,  to the  then  holders  of the  Senior  Indebtedness  on the  basis of the
respective  amounts of such Senior  Indebtedness  held by such  holder,  and the
holder of this Note hereby  agrees to execute all  documents  that such  holders
request in order to  evidence  such  assignment,  provided,  however,  that such
assignment  shall  terminate  upon receipt by such holders of payment in full of
all of the Senior  Indebtedness.  While such  assignment is in effect,  the then
holders of the Senior  Indebtedness  shall have the exclusive  right to exercise
all rights of the holder of this Note  arising from their claims with respect to
this Note in the Proceeding,  including but not limited to the right to vote for
a  trustee  and to  accept  or  reject  a  proposed  plan of  reorganization  or
composition,  and the holder of this Note hereby agrees to execute all documents
reasonably  requested by the then holders of the Senior Indebtedness in order to
exercise any such rights whether (at the sole discretion of such holders) in the
holder's  own  name  or in the  name of the  holder  of this  Note.  While  such
assignment is in effect, the holder of this Note also agrees that it shall, upon
request  of a holder of Senior  Indebtedness,  and at its own  expense  take all
reasonable  actions  (including  but not limited to the  execution and filing of
documents  and the giving of  testimony in any  Proceeding,  whether or not such
testimony  could have been  compelled  by process)  necessary  to prove the full
amount of all its  claims in any  Proceeding,  and the holder of this Note shall
not  expressly,  by implication or by inaction waive any claim in any Proceeding
with respect to this Note without the written consent of such holder.

     (ii)Upon  payment or distribution to creditors in a Proceeding of assets of
the Company of any kind or character,  whether in cash,  property or securities,
all principal and interest due upon any Senior  Indebtedness shall first be paid
in full, or payment thereof in full duly provided for, before the holder of this
Note shall be  entitled  to receive  or, if  received,  to retain any payment or
distribution on account of this Note; and upon any such Proceeding,  any payment
or  distribution  of assets of the Company of any kind or character,  whether in
cash, property or securities, to which the holder of this Note would be entitled
except for the  provisions  of this Section 1 shall be paid by the Company or by
any receiver, trustee in bankruptcy,  liquidating trustee, agent or other person
making  such  payment or  distribution,  or by the holder of this Note who shall
have  received  such  payment or  distribution,  directly  to the holders of the
Senior Indebtedness (pro rata to each such holder on the basis of the respective
amounts   of  such   Senior   Indebtedness   held  by  such   holder)  or  their
representatives  to the extent necessary to pay all such Senior  Indebtedness in
full after giving effect to any concurrent payment or distribution to or for the
holders of such Senior Indebtedness,  before any payment or distribution is made
to the holder of this Note. In the event of any  Proceeding,  the holder of this
Notes shall be entitled to be paid one hundred  percent  (100%) of the principal
amount thereof and accrued  interest  thereon before any  distribution of assets
shall be made among the holders of any class of shares of the  capital  stock of
the Company in their capacities as holders of such shares.

     (iii) For  purposes of this  Section  1(c),  the words  "assets" and "cash,
property or securities" shall not be deemed to include shares of Common Stock of
the Company as reorganized  or  readjusted,  or securities of the Company or any
other  person  provided for by a plan of  reorganization  or  readjustment,  the
payment of which is subordinated at least to the extent provided in this Section
1 with respect to this Note to the payment of all Senior  Indebtedness which may
at the time be outstanding, if (x) the Senior Indebtedness is assumed by the new
person, if any, resulting from any such reorganization or readjustment,  and (y)
the rights of the holders of Senior Indebtedness are not, without the consent of
such holders, altered by such reorganization or readjustment.

     (d) Subrogation. Subject to payment in full of all Senior Indebtedness, the
holder of this Note shall be  subrogated  to the rights of the holders of Senior
Indebtedness to receive  payments or  distributions of the assets of the Company
made on such Senior  Indebtedness  until all principal and interest on this Note
shall be paid in full;  and for  purposes  of such  subrogation,  no payments or
distributions  to the holders of Senior  Indebtedness  of any cash,  property or
securities  to which any  holder of this Note would be  entitled  except for the
subordination  provisions of this Section 1 shall, as between the holder of this
Note and the Company  and/or its creditors  other than the holders of the Senior
Indebtedness, be deemed to be a payment on account of the Senior Indebtedness.

     (e) Rights of Holders Unimpaired.  The provisions of this Section 1 are and
are intended  solely for the  purposes of defining  the  relative  rights of the
holder of this Note and the holders of Senior  Indebtedness  and nothing in this
Section 1 shall impair,  as between the Company and the holder of this Note, the
obligation of the Company,  which is unconditional  and absolute,  to pay to the
holder of this Note the principal  thereof and interest  thereon,  in accordance
with the terms of this Note,  nor shall  anything  herein  prevent the holder of
this Note from exercising all remedies otherwise  permitted by applicable law or
hereunder  upon  default,  subject to the  rights set forth  above of holders of
Senior Indebtedness to receive cash, property or securities otherwise payable or
deliverable to the holder of this Note.

     (f) Payments on  Subordinated  Notes.  Subject to Section 1(c), the Company
may make  payments  of the  principal  of, and any  interest or premium on, this
Note, if at the time of payment,  and  immediately  after giving effect thereto,
(i)  there  exists  no  default  in any  payment  with  respect  to  any  Senior
Indebtedness  and (ii) there shall not have occurred an event of default  (other
than a default in the payment of amounts due thereon) with respect to any Senior
Indebtedness,  as defined in the instrument under which the same is outstanding,
permitting the holders thereof to accelerate the maturity thereof, other than an
event of default  which  shall have been cured or waived or shall have ceased to
exist.

2.  Repayment  and  Prepayment  of  Principal.   Subject  to  the  subordination
provisions of Sections 1(a),  1(b1) and 1(c) (but, for purposes of clarity,  not
Section 1(b2)) and the following  sentence,  all amounts due under this Note may
be prepaid in whole or in part,  without the prior written consent of the holder
of this  Note.  This Note may not be  repaid  at any time  that  there are loans
outstanding  under the  Credit  Agreement  or prepaid  at any time  without  the
written consent of the holders of Senior  Indebtedness  unless such repayment or
prepayment  is made  solely  out of the  proceeds  from the  issuance  of equity
interests  in  the  Company  or  notes   containing   subordination   provisions
subordinating  the  notes to the  Senior  Indebtedness  at  least to the  extent
provided  in Section 1 (other than  Section  1(b2)).  Notwithstanding  any other
provision  hereof,  the  Company  shall  repay or prepay to the holder  promptly
following the  expiration of the tender offer to be conducted by the Company for
shares of Nomai S.A. any amount not used to acquire  shares of capital  stock of
Nomai S.A. in such tender offer.]

3.  Default.  Subject to the  subordination  provisions of Section 1, the entire
unpaid  principal of this Note and the interest  then accrued on this Note shall
become and be  immediately  due and payable upon written demand of the holder of
this Note,  without any other notice or demand of any kind or any presentment or
protest,  and the holder shall have all of the rights and  remedies  afforded by
applicable law, if any one of the following events shall occur and be continuing
at the time of such demand,  whether  voluntarily or involuntarily,  or, without
limitation,  occurring or brought about by operation of law or pursuant to or in
compliance with any judgment, decree or order of any court or any order, rule or
regulation of any governmental body:

     (a) If default  shall be made in the  payment of  principal  or interest on
this Note, and such default shall remain unremedied for thirty (30) days; or

     (b) If the Company (i) makes a composition or an assignment for the benefit
of creditors or trust mortgage,  (ii) applies for,  consents to,  acquiesces in,
files a petition  seeking  or admits  (by  answer,  default  or  otherwise)  the
material allegations of a petition filed against it seeking the appointment of a
trustee, receiver or liquidator, in bankruptcy or otherwise, of itself or of all
or a substantial  portion of its assets, or a  reorganization,  arrangement with
creditors  or other  remedy,  relief or  adjudication  available to or against a
bankrupt,  insolvent or debtor under any bankruptcy or insolvency law or any law
affecting  the rights of  creditors  generally,  or (iii)  admits in writing its
inability to pay its debts generally as they become due; or

     (c) If the Company  shall not have granted to the holder hereof a valid and
enforceable  security  interest in all of the  Company's  now owned or hereafter
acquired material intellectual property and a perfected security interest in the
Company's  issued and pending United States  patents,  United States  registered
trademarks and intellectual  property  constituting  general intangibles (within
the meaning of the  Uniform  Commercial  Code,  as adopted in the State of Utah)
which is deemed located in the United States, which is junior and subordinate to
a security  interest in the same  property in favor of the holders of the Senior
Indebtedness  within  the  earlier  of  forty-five  (45) days from the date that
written demand for the security interest described herein is made in writing and
ten (10) days of the granting and  perfecting  of a security  interest in any of
the  property  described  herein to secure  payment of amounts  owing  under the
Credit Agreement; or

     (d) If the indebtedness represented by the Credit Agreement becomes due and
payable prior to the stated maturity thereof; or

     (e) If an order for relief shall have been entered by a bankruptcy court or
if a decree,  order or judgment  shall have been entered  adjudging  the Company
insolvent,  or  appointing  a receiver,  liquidator,  custodian  or trustee,  in
bankruptcy  or  otherwise,  for it or for all or a  substantial  portion  of its
assets, or approving the winding-up or liquidation of its affairs on the grounds
of insolvency or nonpayment of debts, and such order for relief,  decree,  order
or judgment  shall  remain  undischarged  or unstayed for a period of sixty (60)
days; or if any  substantial  part of the property of the Company is sequestered
or attached and shall not be returned to the  possession  of the Company or such
subsidiary or released from such attachment within sixty (60) days.

4. General.

     (a) Successors and Assigns.  This Note, and the  obligations  and rights of
the  Company  hereunder,  shall be binding  upon and inure to the benefit of the
Company,  the holder of this Note, and their  respective  heirs,  successors and
assigns;  provided  however,  that the  original  holder of this Note  shall not
transfer or assign any  interest  herein to any other  person or entity prior to
the  time,  if  any,  that  a  default  has  occurred   hereunder,   except  for
distributions by the holder to its partners or by its partners to their estates,
heirs or partners.

     (b) Recourse.  Recourse  under this Note shall be to the general  unsecured
assets  of the  Company  only  and in no  event to the  officers,  directors  or
stockholders of the Company.

     (c) Changes. Changes in or additions to this Note may be made or compliance
with any term, covenant, agreement,  condition or provision set forth herein may
be omitted or waived  (either  generally or in a particular  instance and either
retroactively  or  prospectively),  upon written  consent of the Company and the
holder of this Note.

     (d)  Currency.  All payments  shall be made in such coin or currency of the
United States of America as at the time of payment shall be legal tender therein
for the payment of public and private debts.

     (e)  Set-off.  All  payments by the  Company  under this Note shall be made
without set-off or counterclaim  and be free and clear and without any deduction
or  withholding  for any  taxes  or  fees of any  nature  whatever,  unless  the
obligation to make such deduction or withholding is imposed by law.

     (f) Costs of  Collection.  The Company agrees to pay on demand all costs of
collection, including reasonable attorneys' fees, incurred by the holder of this
Note in enforcing the obligations of the Company under this Note.

     (g) Waivers. No delay or omission on the part of the holder of this Note in
exercising  any right under this Note shall operate as a waiver of such right or
of any other right of such  holder,  nor shall any delay,  omission or waiver on
any one  occasion be deemed a bar to or waiver of the same or any other right on
any future occasion.

     (h) Notices. All notices,  requests,  consents and demands shall be made in
writing  and shall be mailed  postage  prepaid,  or  delivered  by hand,  to the
Company or to the holder hereof at their respective addresses set forth below or
to such other address as may be furnished in writing to the other party hereto:

                  If to the holder:

                  Idanta Partners
                  4660 La Jolla Village Drive
                  San Diego, CA 92122
                  Attention: Controller

                  If to the Company:

                  Iomega Corporation
                  1821 West Iomega Way
                  Roy, UT 84067
                  Attention: General Counsel

     (i)  Saturdays,  Sundays,  Holidays.  If any  date  that may at any time be
specified  in this Note as a date for the making of any payment of  principal or
interest  under this Note shall  fall on  Saturday,  Sunday or on a day which in
Roy, Utah shall be a legal holiday, then the date for the making of that payment
shall be the  next  subsequent  day  which is not a  Saturday,  Sunday  or legal
holiday.

     (j) Governing  Law. This Note shall be construed and enforced in accordance
with,  and the rights of the parties shall be governed by, the laws of the State
of Delaware.
<PAGE>

         IN WITNESS  WHEREOF,  this Note has been  executed  and  delivered as a
sealed  instrument  on the date  first  above  written  by the  duly  authorized
representative of the Company.

                                                     IOMEGA CORPORATION



                                                 By:/s/ Robert J. Simmons
                                                    Robert J. Simmons
                                                    Vice President and Treasurer


ATTEST:  /s/ Laurie B. Keating
         Secretary