<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE
ACCOMPANYING FINANCIAL STATEMENTS AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE
TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<RESTATED>
<MULTIPLIER> 1,000
       
<S>                             <C>                     <C>                     <C>                     <C>
<PERIOD-TYPE>                   YEAR                    9-MOS                   6-MOS                   3-MOS
<FISCAL-YEAR-END>                          APR-30-1997             APR-30-1997             APR-30-1997             APR-30-1997
<PERIOD-START>                             MAY-01-1996             MAY-01-1996             MAY-01-1996             MAY-01-1996
<PERIOD-END>                               APR-30-1997             JAN-25-1997             OCT-26-1996             JUL-27-1996
<CASH>                                          14,575                  11,986                   7,945                  11,104
<SECURITIES>                                    19,100                  16,149                  24,987                  21,176
<RECEIVABLES>                                   18,078                  17,930                  18,467                  17,277
<ALLOWANCES>                                       249                     215                     213                     250
<INVENTORY>                                     11,798                  12,849                  12,955                  12,496
<CURRENT-ASSETS>                                67,718                  63,581                  60,741                  54,097
<PP&E>                                          70,945                  71,112                  69,454                  68,097
<DEPRECIATION>                                  42,141                  41,751                  40,617                  39,198
<TOTAL-ASSETS>                                 105,580                 102,157                  99,510                  93,590
<CURRENT-LIABILITIES>                           14,386                  12,627                  12,705                   9,658
<BONDS>                                              0                       0                       0                       0
<PREFERRED-MANDATORY>                                0                       0                       0                       0
<PREFERRED>                                          0                       0                       0                       0
<COMMON>                                        11,623                  11,623                  11,623                  11,623
<OTHER-SE>                                      75,666                  73,902                  71,611                  69,049
<TOTAL-LIABILITY-AND-EQUITY>                   105,580                 102,157                  99,510                  93,590
<SALES>                                        121,480                  88,675                  59,194                  28,910
<TOTAL-REVENUES>                               121,480                  88,675                  59,194                  28,910
<CGS>                                           62,342                  45,395                  30,071                  14,747
<TOTAL-COSTS>                                   62,342                  45,395                  30,071                  14,747
<OTHER-EXPENSES>                                41,844                  30,498                  20,497                   9,963
<LOSS-PROVISION>                                     0                       0                       0                       0
<INTEREST-EXPENSE>                                   0                       0                       0                       0
<INCOME-PRETAX>                                 19,080                  14,043                   9,427                   4,550
<INCOME-TAX>                                     6,585                   4,843                   3,252                   1,590
<INCOME-CONTINUING>                             12,495                   9,200                   6,175                   2,960
<DISCONTINUED>                                       0                       0                       0                       0
<EXTRAORDINARY>                                      0                       0                       0                       0
<CHANGES>                                            0                       0                       0                       0
<NET-INCOME>                                    12,495                   9,200                   6,175                   2,960
<EPS-PRIMARY>                                      .55<F1>                 .40<F1>                 .27<F1>                 .13<F1>
<EPS-DILUTED>                                      .55<F1>                 .40<F1>                 .27<F1>                 .13<F1>
<FN>
<F1>THIS STATEMENT HAS BEEN RESTATED AS A RESULT OF SFAS NO. 128, EARNINGS PER
SHARE, AND APPLICABLE STOCK SLPITS.
</FN>
        

</TABLE>