?¨??????×???(USB)??×?1997?ê????????PC?÷°??ù????????????·?????±ê×???1998?ê????????????????I/O????????USB?°????????????Apple iMac??×?????USB±ê×?(1.0?°1.1)?§????×??ó????????????1M×?????????????????12 Mbps??Windows 98??×????§??USB????×÷???????ü???????÷???è±??????????ò??????°ü?¨?ó±ê???ü???°???ù?÷??2000?ê4????USB??????????(USB-IF???±°ü?¨:???í??????????·???????????????°???NEC?°????)·?????USB±ê×?2.0????°?±???????????????????????????USB????×???????????480 Mbps??±?USB 1.1??×????????ì40±???


ISO??????????
????USB?§???????à???????????????ó?????é(bulk)????·???????????????????????????????????(isochronous??ISO)????·????????????í?±???????????????????????é???????·±????????????????????á???§?ò?????????????????·±????¨?±?????????????????????????????????÷???±???é??????????????????×????????????????????????????÷?úPC???è±??à?????÷?·?¨???????????????????????????á????????????????????????????
?????????????????????????é??????????·????ò?????????????????ê??????×????????????????é????????????????×??±????????±?×??·???ü???????°??????????ISO???????????§??????????ISO???????????????ò??ISO????×??±·??????????????????ú???í·??????·???????????????????°?±?????????????ò?????á?????????ù±????????????é???????°?????????÷?????????ò????×??????§????????????×?±??????°·????±???ó???????????????????????????????????????§???????????????§????????±????????????±??????
????USB???í±?·???????1000????USB 1.1???????????????????????????????è±?????????????????°ü??×??ó??°ü?ó????1023×?????????×?????????????1 Mbps??USB 2.0?????????????á????480 Mbps????????????·???8?????????????????è±????????è?ó??USB 2.0?????????è±???????????1024×?????°ü???????ó??3??????°ü???????????ùUSB 2.0??ISO????????1 Mbps?á????24 Mbps (????1000?? ?? ????8???? ?? ??????3??????°ü ?? ??????°ü1024×???)??

ISO??????????
????USB 2.0????ISO?????ó?§????×????ú?·±???????°??ó???????ú??USB?????ú????????????????USB?????í??????????????????·?±????°???????ó?§?ù????????USB?????ú?????í??????????5??????????????????CIF (352 ?? 288)?????????è±??è????90%?????????í???????????í?????????ù??USB?è±????í???????¨??????ISO???à???????ú????????30?????????¤×÷???????????????í??10%??×÷??????????????????????DV(????????)?????ú????????????????????4.5Mbyte?????¨????????????????????????????ISO?????????à?ì?ò???ê?????????à????1?ù?????÷?à?÷???é?ù?è???í??USB1.1?????°USB2.0?????ù????????ISO???í????±??é????
????USB??×÷????·???????????CPU?±??????????USB 2.0??????????????CPU????????????????DVD-RAM?òCDRW?????÷???????è±?????????????USB 2.0±ê×????ó???????????è±?????????????????20 Mbps???????????????á????
????Windows?§????USB?ù??·????á?????????ù?è???????è±?????????×????????????è?????è±???????·????á????×??×????USBD?????¨??????×?????????????USBD?????????à????(class drivers)???????????????????à?????????è±????¨?????????§??ISO???à????±????????÷?à???????ò?¨Stream Class Driver??stream.sys???????????????????ò????stream.sys??????Windows 98°ü?????????????è±????§??????Windows 2000??ME??XP?ò?¨????????????×÷???????????????????????????????????????§????????Windows(r) 2000??ME??XP?????????????§???????????à?ú????????USB 2.0?????è±????????÷????????????24 Mbps?????í??
?????§??USB 2.0??·???PCI?÷?ú???????ê??????·????????????????§??USB 2.0??±ê×??????????÷????????????·?????????Cypress??EZ-USB FX2(tm)??????????????USB 2.0??·?????????????????24Mbyte??????????????ISO??????8?????????÷?????÷?????????é??????????????????±??????????????úASIC?¨×¨?????????·?????????à???????????à?????????÷??????·??¤??°ü??°ü?¨???????????????????ò·??????????ú??????ISO????·????????????ì??±??¤???§????·??????????í????????ISD-300??USB 2.0?÷?????ú?ú???????è????????????????±????íIDE?????÷???????÷?ü?ì??????CDRW??DVD?????÷??