campbell@redsox.bsw.com (Larry Campbell) (05/26/90)
I'm using a CDC/Imprimis/Seagate Wren VI on a WD1007V ESDI controller. The controller claims to be a 15Mb/s board. Recently someone (sorry, forgot who) in this group said that if you had a 15Mb/s controller, you could jumper the drive for 93 sectors/track, raising its capacity from about 650MB to about 1.1GB (actually they said 770MB, but 1630 cyl * 93 sec/trk * 15 heads comes out to about 1.1GB). Now, the drive *does* have a jumper labelled 93 sectors/track. However, I had originally jumpered the drive for 54 sectors/track (the other choices are 53, 35, and 34). At 54 sectors/track the thing ran *ridiculously* slowly; a low level format would have taken (if I had waited for it to finish) over 122 hours! I called Western Digital and was told that the controller "isn't fast enough" to run at 54 sectors/track, and if I jumpered the drive for 53 sectors/track it would run at a reasonable speed. Well, I was skeptical, but I tried it, and indeed it now runs like a champ. Very nice drive. Now, if the WD1007V can't hack 54 sectors, I suspect it *certainly* can't hack 93. So here (finally) is my question. Is the WD1007V a bozo controller, or am I doing something wrong? Can I actually use 93 sectors/track on my drive, and if I need a new controller to do so, which controller will work? -- Larry Campbell The Boston Software Works, Inc. campbell@redsox.bsw.com 120 Fulton Street wjh12!redsox!campbell Boston, MA 02109
davidsen@sixhub.UUCP (Wm E. Davidsen Jr) (05/27/90)
In article <1576@redsox.bsw.com> campbell@redsox.bsw.com (Larry Campbell) writes: | I'm using a CDC/Imprimis/Seagate Wren VI on a WD1007V ESDI controller. The | controller claims to be a 15Mb/s board. I believe there are 10 and 15 versions of this board. All of ours are 10 so far. | Now, the drive *does* have a jumper labelled 93 sectors/track. | Now, if the WD1007V can't hack 54 sectors, I suspect it *certainly* can't | hack 93. | | So here (finally) is my question. Is the WD1007V a bozo controller, or am | I doing something wrong? Can I actually use 93 sectors/track on my drive, | and if I need a new controller to do so, which controller will work? We have had good luck with the CompuAdd cached controller. It's pricey, but seems to work. Warning! If you have enough memory in your system to provide a few MB of disk buffers, you will see precious little improvement using the CA. You will get a LOT of improvement if you are running a small memory system. The 744MB is 93 sectors, 16 heads, 1024 tracks. The 1.2GB model is another part number. I am told that the 766MB model is a 1.2GB unit which would not run 93 sectors in the tracks>1024. I have no idea if that is true, but the numbers fit. If I had one of these (and I'm so sick of being out of disk that's it's getting close), I would definitely give it a try. Lots of disks run beyond spec, the ST4096 (usually) runs RLL, the Maxtor 1140 usually runs 1224 tracks (but I never saw one run RLL). I would certainly try it. -- bill davidsen - davidsen@sixhub.uucp (uunet!crdgw1!sixhub!davidsen) sysop *IX BBS and Public Access UNIX moderator of comp.binaries.ibm.pc and 80386 mailing list "Stupidity, like virtue, is its own reward" -me
sl@van-bc.UUCP (Stuart Lynne) (05/29/90)
In article <1576@redsox.bsw.com> campbell@redsox.bsw.com (Larry Campbell) writes: >I'm using a CDC/Imprimis/Seagate Wren VI on a WD1007V ESDI controller. The >Now, if the WD1007V can't hack 54 sectors, I suspect it *certainly* can't >hack 93. > >So here (finally) is my question. Is the WD1007V a bozo controller, or am >I doing something wrong? Can I actually use 93 sectors/track on my drive, >and if I need a new controller to do so, which controller will work? NO, the problem is the overhead associated with each sector. The ESDI drive doesn't particularily care how many bytes you associate with each sector. You basically get a certain amount, for example 31,410 bytes on my XT-8760E. And can you divide it up how you like. (So the maximum in theory for my Maxtor is 61 512 bytes sectors.) Unfortunately the controller has overheads, so that it needs to use more than 512. In the case of the 1007V, it can support up to 54 spt so the overhead is something like 69 bytes (it needs 581 bytes per sector). The 1007V actually will run and allow you to use 54spt. But unfortunately the speed of the 1007V is such that it can't quite keep up so performance is poor (one sector per revolution). If you reduce the speed by lowering the number of sectors per track to 53 it runs at full speed (full track per revolution). -- Stuart.Lynne@wimsey.bc.ca ubc-cs!van-bc!sl 604-937-7532(voice) 604-939-4768(fax)