Path: utzoo!utgpu!attcan!uunet!husc6!mailrus!ames!vsi1!octopus!pete From: pete@octopus.UUCP (Pete Holzmann) Newsgroups: comp.sys.ibm.pc Subject: Re: Recommendations wanted for large (>100 Mb) hard disks Message-ID: <357@octopus.UUCP> Date: 29 Sep 88 04:59:14 GMT References: <29.233DBDD4@busker.FIDONET.ORG> <3995@tekgvs.GVS.TEK.COM> <11769@emerald.BBN.COM> Reply-To: pete@octopus.UUCP (Pete Holzmann) Distribution: na Organization: Octopus Enterprises, Cupertino CA Lines: 41 It *is* DOS that can't handle more than 1024 cylinders. You need a device driver that hides the extra cylinders somehow. The most common method seems to be to have a custom device driver (Ontrack=DMDRVR.SYS, Speedstor=HARDRIV.SYS, Adaptec boards come with ADAPTEC.SYS) that can access above 1024 cylinders and make them look like an extra physical disk to DOS. The best and cheapest version I've seen is to get an Adaptec controller of your choice. Its low level format program (built into the ROM BIOS) can handle all this, including download of the device driver onto your disk! Another method is to fake everything up to make it look like there are fewer cylinders. As mentioned elsewhere, Future Domain can use larger sector sizes and act as if there are fewer cylinders (i.e. tell the operating system that you've got a normal number of sectors per track, but actually have only 1/4 as many or whatever, and do the translation on the fly). Personally, I like what some others have done, including Adaptec in their latest BIOS revs: they use normal sector sizes, but you can fake things up so it looks like there are 63 sectors per track; the board does the logical to physical translation on the fly as with the big-sector method. What is nice about this method is that you don't waste a gob of space for each small file on your system, and random record access needn't suffer from pulling in a giant sector when you only need a small chunk of data. Anyway, handling cylinders beyond 1024 is not too big an issue any more, as long as you are using the latest rev levels of SpeedStore, Disk Manager, and most main stream controllers. By the way: the wholesale price on Adaptec 2372 controllers dropped 35-40 bucks recently, presumably due to volume. This should show up real soon in regular pricing, making 1:1 RLL only about 20 bucks more expensive than ST506! Pete -- OOO __| ___ Peter Holzmann, Octopus Enterprises OOOOOOO___/ _______ USPS: 19611 La Mar Court, Cupertino, CA 95014 OOOOO \___/ UUCP: {hpda,pyramid}!octopus!pete ___| \_____ Phone: 408/996-7746