
<PAGE>   1
 
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                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

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                                SCHEDULE 14D-1/A
     TENDER OFFER STATEMENT (AMENDMENT NO. 1) PURSUANT TO SECTION 14(d)(1)
                     OF THE SECURITIES EXCHANGE ACT OF 1934
 
                                 SCHEDULE 13D/A
                               (AMENDMENT NO. 3)
                           (PURSUANT TO SECTION 13(d)
                  OF THE SECURITIES AND EXCHANGE ACT OF 1934)

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                               AMDAHL CORPORATION
                                    (ISSUER)
 
                          FUJITSU INTERNATIONAL, INC.
                                FUJITSU LIMITED
                                   (BIDDERS)

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                     COMMON STOCK, PAR VALUE $.05 PER SHARE
                         (TITLE OF CLASS OF SECURITIES)

                            ------------------------
 
                                  023905 10 2
                     (CUSIP NUMBER OF CLASS OF SECURITIES)

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                                 TAKASHI TAKAYA
                          DIRECTOR AND GROUP PRESIDENT
                  CORPORATE PLANNING AND BUSINESS DEVELOPMENT
                                FUJITSU LIMITED
                           MARUNOUCHI CENTER BUILDING
                            6-1, MARUNOUCHI 1-CHOME
                          CHIYODA-KU, TOKYO 100, JAPAN
                           TELEPHONE: 81-3-3216-0570
          (NAME, ADDRESS AND TELEPHONE NUMBER OF PERSONS AUTHORIZED TO
            RECEIVE NOTICES AND COMMUNICATIONS ON BEHALF OF BIDDER)

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                                    COPY TO:
                            ROBERT S. TOWNSEND, ESQ.
                            MORRISON & FOERSTER LLP
                               425 MARKET STREET
                      SAN FRANCISCO, CALIFORNIA 94105-2482
                           TELEPHONE: (415) 268-7080

 
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        This Amendment No. 1 to the Tender Offer Statement on Schedule 14D-1
(the "Schedule 14D-1") of Fujitsu Limited, a Japanese corporation (the
"Parent"), and Fujitsu International, Inc., a Delaware corporation and a wholly
owned subsidiary of the Parent (the "Purchaser"), dated August 5, 1997, and
Amendment No. 3 to Schedule 13D (the "Schedule 13D") of the Parent, dated March
24, 1993, amend and supplement the Schedule 14D-1 and the Schedule 13D. The
Schedule 14D-1 and the Schedule 13D relate to the tender offer by the Purchaser
to purchase any and all outstanding shares of common stock, par value $.05 per
share (the "Shares"), of Amdahl Corporation, a Delaware corporation, at a price
of $12.00 per Share, net to the seller in cash, upon the terms and subject to
the conditions set forth in the Offer to Purchase, dated August 5, 1997, and in
the related Letter of Transmittal. Capitalized terms used and not otherwise
defined herein have the respective meanings given such terms in the Schedule
14D-1.  


ITEM 10.  ADDITIONAL INFORMATION.

        Items 10(b)-(c) are hereby amended and supplemented by addition of the
following information thereto:

        A copy of the Parent's press release with respect to the early
termination of the waiting period under the HSR Act is filed as Exhibit (a)(10)
to this Statement and is incorporated herein by reference.


ITEM 11.  MATERIAL TO BE FILED AS EXHIBITS.

        (a)(10)  Press release dated August 14, 1997, issued by the Parent.
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                                   SIGNATURE
 
     After due inquiry and to the best of the undersigned's knowledge and
belief, the undersigned certifies that the information set forth in this
statement is true, complete and correct.
 
Dated: August 14, 1997
                                          FUJITSU LIMITED
 
                                          By: /s/ Kazuto Kojima
                                            ------------------------------------
                                          Name: Kazuto Kojima
                                          Title:  Director and Group President
                                              Marketing Group and International
                                              Computer Business Group
 
                                          FUJITSU INTERNATIONAL, INC.
 
                                          By: /s/ Kazuto Kojima
                                            ------------------------------------
                                          Name: Kazuto Kojima
                                          Title:  President
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                                  EXHIBIT LIST
 
<TABLE>
<CAPTION>
 EXHIBIT                                                                                 PAGE
 NUMBER                                     DESCRIPTION                                 NUMBER
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<S>          <C>                                                                        <C>
(a)(1)*      Form of Offer to Purchase, dated August 5, 1997.
(a)(2)*      Form of Letter of Transmittal.
(a)(3)*      Form of Letter from Lehman Brothers Inc. to Brokers, Dealers, Commercial
             Banks Trust Companies and Other Nominees.
(a)(4)*      Form of Letter from Brokers, Dealers, Commercial Banks, Trust Companies
             and Other Nominees to Clients.
(a)(5)*      Form of Notice of Guaranteed Delivery.
(a)(6)*      Form of Guidelines for Certification of Taxpayer Identification Number on
             Substitute Form W-9.
(a)(7)*      Summary Advertisement as published in The Wall Street Journal on August
             5, 1997.
(a)(8)       Text of Joint Press Release, dated July 30, 1997, issued by Fujitsu
             Limited and Amdahl Corporation(1)
(a)(9)*      Text of Joint Press Release, dated August 5, 1997, issued by Fujitsu
             Limited and Amdahl Corporation.
(a)(10)      Press Release, dated August 14, 1997, issued by Fujitsu Limited.
(b)          Not applicable.
(c)(1)       Agreement and Plan of Merger, dated as of July 30, 1997, by and among
             Fujitsu Limited, Fujitsu International, Inc. and Amdahl Corporation
             (incorporated herein by reference to Exhibit III to the Offer to Purchase
             filed as Exhibit (a)(1) hereto).
(c)(2)       Confidentiality Agreement, dated June 30, 1997, between Fujitsu Limited
             and Amdahl Corporation(1).
(c)(3)       Letter Agreement, dated July 9, 1997, between Fujitsu Limited and Amdahl
             Corporation(1).
(c)(4)*      Amdahl/Fujitsu 1982 Agreement, dated March 4, 1982, between Fujitsu
             Limited and Amdahl Corporation.
(c)(5)*      Letter Agreement, dated April 3, 1984, between Fujitsu Limited and Amdahl
             Corporation.
(d)          Not applicable.
(e)          Not applicable.
(f)          Not applicable.
</TABLE>
 
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  * Previously filed.

(1) Filed as an Exhibit to Amendment No. 1 to the Schedule 13D filed by Fujitsu
    Limited with the Securities and Exchange Commission on July 31, 1997 and
    incorporated herein by reference.
