<PAGE> 1
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
Schedule 13G
Under the Securities Exchange Act of 1934
(Amendment No.: 1 )*
Name of issuer: IKOS Systems, Inc.
Title of Class of Securities: Common Stock
CUSIP Number: 451716203
Check the following [space] if a fee is being paid with this statement:
n/a. (A fee is not required only if the filing person: (1) has a
previous statement on file reporting beneficial ownership of more than
five percent of the class of securities described in Item 1; and (2)
has filed no amendment subsequent thereto reporting beneficial
ownership of five percent or less of such class.) (See rule 13d-7.)
*The remainder of this cover page shall be filled out for a reporting
person's initial filing on this form with respect to the subject class
of securities, and for any subsequent amendment containing information
which would alter the disclosures provided in a prior cover page.
The information required in the remainder of this cover page shall not
be deemed to be "filed" for the purpose of Section 18 of the Securities
Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of
that section of the Act but shall be subject to all other provisions of
the Act (however, see the Notes).
(Continued on the following page(s))
Page 1 of 4 Pages
<PAGE> 2
13G
CUSIP No.: 451716203
1. NAME OF REPORTING PERSON
S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
Vanguard Explorer Fund
2. CHECK THE APPROPRIATE [LINE] IF A MEMBER OF A GROUP
A. B. X
3. SEC USE ONLY
4. CITIZENSHIP OF PLACE OF ORGANIZATION
Delaware
(For questions 5-8, report the number of shares beneficially owned by each
reporting person with:)
5. SOLE VOTING POWER
156,400
6. SHARED VOTING POWER
-0-
7. SOLE DISPOSITIVE POWER
-0-
8. SHARED DISPOSITIVE POWER
156,400
9. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
156,400
10. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES
N/A
11. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
1.90
12. TYPE OF REPORTING PERSON
IV
Page 2 of 4 Pages
<PAGE> 3
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
----------
SCHEDULE 13G
Under the Securities Act of 1934
----------
Check the following [line] if a fee is being paid with this statement n/a
Item 1(a) - Name of Issuer:
IKOS Systems, Inc.
Item 1(b) - Address of Issuer's Principal Executive Offices:
19050 Pruneridge Avenue, Cupertino, CA 95014
Item 2(a) - Name of Person Filing:
Vanguard Explorer Fund
Item 2(b) - Title of Class of Securities:
Common Stock
Item 2(e) - CUSIP Number
451716203
Item 3 - Type of Filing:
This statement is being filed pursuant to Rule 13d-1. The person filing
is an investment company registered under Section 8 of the Investment Company
Act.
Item 4 - Ownership:
(a) Amount Beneficially Owned:
156,400
(b) Percent of Class:
1.90
Page 3 of 4 Pages
<PAGE> 4
(c) Number of shares as to which such person has:
(i) sole power to vote or direct to vote: 156,400
(ii) shared power to vote or direct to vote: -0-
(iii) sole power to dispose of or to direct the disposition of: -0-
(iv) shared power to dispose or to direct the disposition of: 156,400
Item 5 - Ownership of Five Percent or Less of a Class:
The reporting person has ceased to be the beneficial owner of more than five
percent of the class of securities (X).
Item 6 - Ownership of More Than Five Percent on Behalf of Another Person:
Not applicable
Item 7 - Identification and Classification of the Subsidiary Which Acquired The
Security Being Reported on by the Parent Holding Company:
Not applicable
Item 8 - Identification and Classification of Members of Group:
Not applicable
Item 9 - Notice of Dissolution of Group:
Not applicable
Item 10 - Certification:
By signing below I certify than, to the best of my knowledge and
belief, the securities referred to above were acquired in the ordinary course of
business and were not acquired for the purpose of and do not have the effect of
changing or influencing the control of the issuer of such securities and were
not acquired in connection with or as a participant in any transaction having
such purpose or effect.
Signature
After reasonable inquiry and to the best of my knowledge and belief, I
certify that the information set forth in this statement is true, complete and
correct.
Date 2-12-1999 By /s/ Raymond J. Klapinsky
- ---- --------- ------ --------------------
Raymond J. Klapinsky
Page 4 of 4 Pages
