Xref: utzoo comp.sys.att:7512 unix-pc.general:3698 Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!rutgers!cs.utexas.edu!execu!sequoia!attdso!shuxd!att!cbnewsc!psfales From: psfales@cbnewsc.ATT.COM (Peter Fales) Newsgroups: comp.sys.att,unix-pc.general Subject: Re: 3B1 and 60386 floppies Summary: Further clarifications Message-ID: <3006@cbnewsc.ATT.COM> Date: 7 Sep 89 19:16:14 GMT References: <4137@csd4.csd.uwm.edu> <2986@cbnewsc.ATT.COM> Distribution: na Organization: AT&T Bell Laboratories Lines: 42 In article <2986@cbnewsc.ATT.COM>, psfales@cbnewsc.ATT.COM (Peter Fales) writes: > > It is slightly more difficult to go the other way, because > you have to make sure that there is a VHB on the 3b1 disk. One > way is to format on the 3b1, then write the disk on the 6386, > finally reading it back in on the 3b1. Alternatively, you can > keep on copy of the 3b1 boot track on the 6386 and write it out > when necessary. It has been pointed out to me that I forgot to mention the warnings about interchanging disks between 40 and 80 track disk drives. In particular my comment about formatting on the 3b1, writing on the 6386, and reading on the 3b1 is risky (though it may work). The rules are these: - 40 track drives have wide heads. 80 track drives have narrow heads. - Anything written with a wide head can be read (with high confidence) by either a narrow or a wide head. - Anything written by a narrow head on a new (out of the box) or bulk-erased disk can likely be read by either a wide or narrow head. - Anything written by a narrow head down the middle of a wide track previously written on a 40 track drive can likely be read by the narrow head. But if read on a 40 track drive, the head will pick up both the original data and the new data written down the middle. This may cause problems, though in practice you can sometimes get away with it. Summary: If you are just trying to transfer data from machine to another, and the data on the floppy is not critical you may not need to worry. If your only copy of the data is on the floppy, writing on both 40 and 80 track drives is risky at best. -- Peter Fales AT&T, Room 5B-420 2000 N. Naperville Rd. UUCP: ...att!peter.fales Naperville, IL 60566 Domain: peter.fales@att.com work: (312) 979-8031