Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!utgpu!water!watmath!clyde!rutgers!ames!aurora!labrea!decwrl!hplabs!parcvax!burton From: burton@parcvax.UUCP Newsgroups: comp.sys.ibm.pc Subject: Re: Using 8 inch floppies on an AT compatible Message-ID: <470@parcvax.Xerox.COM> Date: Sun, 6-Sep-87 00:53:12 EDT Article-I.D.: parcvax.470 Posted: Sun Sep 6 00:53:12 1987 Date-Received: Sun, 6-Sep-87 20:42:23 EDT References: <2211@batcomputer.tn.cornell.edu> <777@custom.UUCP> <2081@bcsaic.UUCP> Reply-To: burton@parcvax.xerox.com.UUCP (Philip M. Burton) Organization: Xerox PARC Lines: 55 In article <2081@bcsaic.UUCP> paula@bcsaic.UUCP (Paul Allen) writes: > > >In article <777@custom.UUCP>, boykin@custom.UUCP (Joseph Boykin) writes: >>In article <2211@batcomputer.tn.cornell.edu>, sparks@batcomputer.tn.cornell.edu (Steve Gaarder) writes: >>> I'm looking for a way to connect a Shugart SA810 half-height single-side >>> 8 inch floppy to an HP Vectra (AT compatible) for the purpose of reading >>> standard CP/M disks. Two questions: >>> >>> 1) Hardware: Since the high-density drive uses the same data rate as an >>> 8 inch drive, can I hook up the drive to the existing controller? >> >>Data rate has little to do with the problem. As a simplistic answer, >>the two cables are different (8" drives have a 50 pin connector, 5 1/4's >>have a 34 pin connector. Although I haven't ever looked into >>this, I doubt very strongly if there is any way to simply reroute >>signals so the two would be compatible. The real answer is that >>the two drives are not compatible with each other. > >[stuff about PC 8" controllers and CPM deleted] > >Once you get the drive hooked up, you should be able to format it as if >it was a 5" DSHD drive. Getting it to talk to CP/M diskettes may be Even if all of the above is correct, there is still one difference between the 8" (double-sided, double density) and the AT high density drive: There are still some differences betweeen 8" and 5 1/4" high density drives. First, the 8" drive has only 77 tracks, and the AT's high density drive has 80 tracks. Second, there was absolutely no standardization in the CP/M world for double- density disks, either SS or DS. (In fact, that was almost a feature -) ) So, to read CP/M disks, you will need to program in various CP/M BIOS para- meters, including the sector size, interleave factor, directory size, etc. All in all, a real pain. Better to pay the man the money, if he will give you a solution that works. And, good luck. Oh, I almost forgot. Some CP/M disks were "hard-sectored". This used an "index hole" for each sector, instead of creating sectors by formatting the disk. I doubt that the PC's or AT's controller could handle those. As I said, good luck. -- Philip Burton burton@parcvax.COM ...!hplabs!parcvax!burton Xerox Corp. preferred path: burton.osbunorth@xerox.COM 408 737 4635 ... usual disclaimers apply ...