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Xref: sserve comp.unix.bsd:3757 comp.sys.ibm.pc.hardware:29273 Newsgroups: comp.unix.bsd,comp.sys.ibm.pc.hardware Path: sserve!manuel!munnari.oz.au!mips!mips!darwin.sura.net!Sirius.dfn.de!math.fu-berlin.de!informatik.tu-muenchen.de!rommel From: rommel@Informatik.TU-Muenchen.DE (Kai-Uwe Rommel) Subject: Re: Another Adaptec Question References: <1992Aug14.192127.13801@adaptx1.UUCP> <7@tama.spec.co.jp> Sender: news@Informatik.TU-Muenchen.DE (USENET Newssystem) Organization: Technische Universitaet Muenchen, Germany Date: Sun, 16 Aug 1992 14:43:41 GMT Message-ID: <1992Aug16.144341.24052@Informatik.TU-Muenchen.DE> Distribution: world,fj,spec Lines: 44 In article <7@tama.spec.co.jp> amurai@tama.spec.co.jp (Atsushi Murai) writes: >ariticle is not ..but) and Fujitsu M2266SA 1.2 GB Disks. Functionality >is good but it looks like loosing a space about 200MB (above 1Gbyte). >And some guy let me know about this is a known problem of 1542B and >Adaptec will be fixed by new board - 1542C. (Oh well.....) >Now a day, A lot of guys try to run 386BSD with this card without know >this problem!!! > >My Question: > > o Is this a hard ware limitaion or a firm ware one ? > o Is there any upgrade pass from 1542B to 1542C(?) ? > o When new board is available ? > o How about 174X for EISA bus ? (normal/extended mode) This is a *software* limitation of the operating system. Some OSes don't handle disks with more than 1024 cylinders. The standard mapping of SCSI disks on the 1542B is to 64 heads and 32 sectors per track, i.e. 1MB per cylinder. So, if you have 1 drive >1GB, it exceeds the 1024 cylinder range. I assume that most Unix systems are able to handle more than 1024 cylinders on a disk. DOS is not, Novell apparently not too. OS/2 1.x also not, while OS/2 2.0 handles this. Adaptec has now a new mapping scheme with 256 heads and 64 sectors per track, i.e. 8MB per cylinder. They provide a BIOS and microcode upgrade for the 1542B (version 3.20), contact them for the files (you have to burn them into EPROM's yourself). The new BIOS uses this scheme only with disks >1GB, however, so they remain compatible with already partitioned/formatted smaller disks. However, as said, Unix systems should generally be able to handle more than 1024 (logical, in this case) cylinders. You may want to try this first. The Unix file system code uses the BIOS only at boot time to determine the drive geometry and to load the kernel. Kai Uwe Rommel /* Kai Uwe Rommel --- rommel@informatik.tu-muenchen.de */ DOS ... is still a real mode only non-reentrant interrupt handler, and always will be. -Russell Williams