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Newsgroups: comp.sys.apple2 Subject: Re: CMS SCSI II card From: dempson@actrix.gen.nz (David Empson) Date: Thu, 30 Jul 1998 00:15:15 +1200 Message-ID: <1dcydg1.15wnjny1w1wosgN@dempson.actrix.gen.nz> References: <1998072715375200.LAA04181@ladder01.news.aol.com> Organization: Empsoft X-Newsreader: MacSOUP 2.3 NNTP-Posting-Host: 202.49.157.176 X-Trace: 30 Jul 1998 00:15:04 -1200, 202.49.157.176 Lines: 45 Path: news1.icaen!news.uiowa.edu!NewsNG.Chicago.Qual.Net!nyd.news.ans.net!newsfeeds.ans.net!news.idt.net!newsfeed.internetmci.com!203.97.37.7!newsfeed.clear.net.nz!news.iprolink.co.nz!news.actrix.gen.nz!dempson Xref: news1.icaen comp.sys.apple2:137430 BiG Tim 80 <bigtim80@aol.com> wrote: > Can anyone tell me if the CMS SCSI II card is any different from the plain > SCSI card, if it is can you tell me how. By the "plain" SCSI card, I assume you mean Apple's original card? The main difference is that the CMS card uses a hard partitioning scheme, which is not compatible with anything else. The jumpers on the card set the number and size of partitions on the drive. Other SCSI cards (Apple and RamFast, also the Macintosh) use a soft partitioning scheme, in which a partition table is written onto the drive and is used by the firmware or device drivers to locate the partitions. These schemes are not compatible with each other, so a partitioned drive used with the CMS card cannot be accessed if the drive is connected to a non-CMS card, and vice versa. (You can repartition the drive, but this will lose all data on it.) A drive which is NOT partitioned should work equally well on CMS and non-CMS cards, but you will be limited to accessing 32 megabytes of a large drive. The Apple/RamFast scheme is much more flexible than the CMS scheme, as you have more options for size and number of partitions. In particular, if you intend to use the CMS card on a IIgs, you cannot create partitions larger than 32 megabytes (e.g. for the HFS file system), and are limited to either two or four partitions (I haven't looked at the details in a while, so I'm not sure which). With the original Apple SCSI card on a IIe (or in ProDOS-8 on a IIgs) you can have up to seven partitions. The theoretical limit is higher for an Apple High-Speed or RamFast SCSI card, but there is a practical limit imposed by drives in other slots. Under GS/OS (on the IIgs), there is a theoretical limit of 63 partitions per drive with all three of these SCSI cards, but the CMS card will be stuck at two or four. -- David Empson dempson@actrix.gen.nz Snail mail: P.O. Box 27-103, Wellington, New Zealand