Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!math.fu-berlin.de!fauern!opal!gmdtub!prosun!tmh From: tmh@prosun.first.gmd.de (Thomas Hoberg) Newsgroups: comp.unix.sysv386 Subject: Re: ISC 2.2.1 + Fujitsu 1.2Gb drive + AHA 1740 EISA SCSI Message-ID: <642@bigfoot.first.gmd.de> Date: 7 May 91 20:27:33 GMT References: <1991Apr30.120043.25022@jet.uucp> <1991May01.114725.14859@virtech.uucp> Sender: news@bigfoot.first.gmd.de Reply-To: tmh@prosun.first.gmd.de (Thomas Hoberg) Organization: GMD-FIRST, D-1000 Berlin 10 Lines: 38 In article <1991May01.114725.14859@virtech.uucp>, cpcahil@virtech.uucp (Conor P. Cahill) writes: |> cm@jet.uucp (colin manning) writes: |> >The Fujitsu 2266 has 1029 cylinders. Although the fdisk table only |> >caters for disks with up to 1024 cylinders, ISC's documentation says |> >that it will use the additional cylinders, if you try to allocate |> >them when partitioning the disk during installation. I had a mail |> >msg some time back from someone who said that this does not work, and |> >furthermore that by attempting to use cylinders >1024, the system will wrap |> >around to cylinder 0 and clobber the start of your disk (which would |> >be *serious*). |> |> The wrap-around problem is not related to 1024 cylinders. It is some |> function of disk size and as far as I know only happens on 1.2GB or |> higher drives. Last I heard ISC knew about the problem and was working |> on it, but that was months ago. Perhaps it has been solved by now. [...] When using the Adaptec UNIX and any other OS care rather little about the physical layout of the disk. The Adaptec will remap any SCSI drive to 32 sectors, 64 heads and as many cylinders as there is megabytes on the disk. This comes rather handy when you are asked by 'fdisk'just how many cylinders you want to allocate for a partition. This induces some latency due to the Adaptecs 8085 having to do some calculations, but with SCSI's defect management a sector might not end up where you believe it should, anyway. With my 1.2GB I am still 'lucky', because it only has about 970MB after formatting, meaning 970 cylinders. Once you got a true 1.2GB drive you are in for trouble, because soft cylinder numbers will actually exceed 1024. On the other hand huge ESDI drive with >1024 cylinders can be made to work with ISC, so it's probably not a big deal to fix it. Until then you will just have to forego some of your disks capacity. -- tom ---- Thomas M. Hoberg | UUCP: tmh@bigfoot.first.gmd.de or tmh%gmdtub@tub.UUCP c/o GMD Berlin | ...!unido!tub!gmdtub!tmh (Europe) or D-1000 Berlin 12 | ...!unido!tub!tmh Hardenbergplatz 2 | ...!pyramid!tub!tmh (World) Germany | BITNET: tmh%DB0TUI6.BITNET@DB0TUI11 or +49-30-254 99 160 | tmh@tub.BITNET