boykin@datagen.UUCP (12/01/83)
I agree that ss disks are probably those which didn't make it through the ds tests. In addition, most of those disks are probably perfectly acceptable to use ds as well as ss. HOWEVER, you say that ds disks are probably not worth the extra money, that's foolish! (I wanted to say something else but decided to keep it clean!). Given the amount of time and effort it takes to i.e. write and debug a program, or compose a letter with your editor, do you really think that saving yourself 20% of a pretty small investment (especially when compared to the overall cost of your system) is worthwhile. Personally, I say no; the risk is too great. My time is valuable and I don't want to rewrite that program, that letter, or even a four line batch file just because my disk can't stand the workout I give it. If it means spending an extra dollar per disk, I believe it's worth the cost. In addition, I'm as foolish to belive that spending a little extra to get high quality disks (I define those to be Maxell or Dysan) rather than junk is also worth the price. Joe Boykin Data General Corp. (Distributed Systems Group) ...(decvax!ittvax, allegra, rocky2)!datagen!boykin
towson%amsaa@sri-unix.UUCP (12/05/83)
From: David Towson (CSD) <towson@amsaa> Joe - In your recent note to the group you discussed your position regarding a perceived risk in using single-side-rated disks in double-sided applications. You mentioned that the small difference in cost between single and double-side- rated disks isn't worth the lost productive time (my paraphrase) incurred when a disk goes sour. I've never had a disk become unreadable after having been successfully written and verified. I have seen them fail post-write-verify, and I've seen bad operating systems go berserk and eat directories. The latter case, of course, has nothing to do with disk quality. In those cases where I have seen disks go bad, they didn't just all-of-a-sudden die; they got flaky - started failing post-write-verify, and required automatic rewriting. So my question to you is this: Given that you have successfully written on a disk, and that the success of the write has been proven by a verify-read, do you still think there is a risk, and if so, what is the mechanism for the failure you fear? Dave
towson%amsaa@sri-unix.UUCP (12/06/83)
From: David Towson (CSD) <towson@amsaa> Interesting indeed! Can anyone explain this? Dave ----- Forwarded message # 1: Received: From Ut-Ngp.ARPA by AMSAA via smtp; 5 Dec 83 20:57 EST Date: Mon, 5 Dec 83 19:53:57 CST From: mknox <mknox@utexas-11.ARPA> Subject: Re: ds vs. ss disks Posted-Date: Mon, 5 Dec 83 19:53:57 CST Message-Id: <8312060159.AA05325@UT-NGP.ARPA> Received: by UT-NGP.ARPA (3.326/3.7) id AA05325; 5 Dec 83 19:59:06 CST (Mon) To: towson@amsaa.ARPA There is a risk, but it is more 'broadband' than using ss disks as DS. I have had the following problem show up on about a dozen Scotch 3M diskettes, all rated DSDD. A diskette will format and test perfectly. Now put it in a drawer for a week (not necessarily the one where you keep the magnets). Now take it out and retest. Bad sector!!! Reformats just fine, tests fine, scenario repeats as necessary. To date I have had this problem ONLY with Scotch, and only about one per thousand or so. But interesting, never-the-less. ----- End of forwarded messages
gil%CCVAX%nosc@sri-unix.UUCP (12/08/83)
Went bad in the drawer. It's a remanence problem that iron oxides have. -gil
ctk@ecsvax.UUCP (12/09/83)
I have at times formatted single sided floppys on double sided 80-track drives with no problems. I worried too much about this and bought some 96-tpi double sided disks. If you're not a worrier I suspect that you'll have few problems. I have a friend who has > 50 single sided disks running on his 80-track drives. He also used to cut holes in them and flip them over when he had only single sided drives.