mentat@ut-ngp.UUCP (Robert Dorsett) (06/06/87)
Is there anything wrong with formatting disks labeled as single-sided as
double-sided? I just upgraded to a Mac Plus and the manual says, quite explic-
itely, "Do NOT" format single-sided disks as double-sided disks. However,
I seem to remember the "official" line being pretty much the same thing with
the Apple II and /// in the early80's, with 5.25" disks. Didn't make a whit
of difference with them: all one had to do was cut out another write-protect
notch so the computer could reference the flip side of the disk. As time went
by, the official line was changed to: "Both sides of a single-sided disk are
identical, but the flip-side is *untested* and *uncertified*." Would I be
incorrect in assuming the same for the 3.5" disks on the Mac? I have well over
200 disks, and am looking forward to recycling a third of them...
--
Robert Dorsett ARPA: mentat@ngp.utexas.edu
The University of Texas at Austin UUCP: {ihnp4,seismo,sally}!ngp!mentat
UTAustin: mentat@walt.cJeenglgspt nthan@apple.UUCP (06/07/87)
In article <5352@ut-ngp.UUCP>, mentat@ut-ngp.UUCP (Robert Dorsett) writes: > Is there anything wrong with formatting disks labeled as single-sided as > double-sided? I just upgraded to a Mac Plus and the manual says, quite > explicitely, "Do NOT" format single-sided disks as double-sided disks. Sure you can go ahead and format single-sided diskettes as double-sided. *****You run the risk of losing data****** Single sided diskettes are validated on one side only. Double sided are validated on both. By saving a few bucks by using single sided diskettes as double, you may lose important data. You do not know when, or even if, but why take a chance for such little savings???? ===================================================================== Byron Han | UUCP: {sun,voder,nsc,mtxinu,dual}!apple!han Apple Computer, Inc. | CSNET: han@apple.csnet 20525 Mariani Ave, | ATTNet: 408-973-6450 Cupertino, CA 95014 | GENIE: BYRONHAN MS 27Y | CSERVE: 72167,1664 ===================================================================== All opinions and statements do not necessarily represent those of my employer, Apple Computer Inc. =====================================================================
tgl@zog.cs.cmu.edu (Tom Lane) (06/07/87)
>Is there anything wrong with formatting disks labeled as single-sided as >double-sided? This seems to come up every 3 months on this newsgroup. The official line is, as you say, that the back side of a SS disk is not tested. It might be OK, then again, it might not. In this situation about all you have to go on is anecdotal evidence, so here's my $0.02 worth: I did it ONCE and got BURNT. This was three or so years ago when DS 3.5" drives were first becoming available. The disks in question were Hewlett-Packard disks, which are made for HP by Sony; Sony has the reputation of being the best brand of disk (see postings in this group a couple of months back concerning independent tests). So it wasn't a case of cheap off-brand disks. It may be that these days SS disks are more likely to be good on the back side. Personally, I wouldn't trust my data to the back of a SS disk. The real bottom line is, as always, how much is that data worth to you? tom lane ----- ARPA: lane@ZOG.CS.CMU.EDU UUCP: ...!seismo!zog.cs.cmu.edu!lane BITNET: lane%zog.cs.cmu.edu@cmuccvma
perry@killer.UUCP (06/10/87)
In article <948@apple.UUCP>, han@apple.UUCP (Byron Han) writes: > In article <5352@ut-ngp.UUCP>, mentat@ut-ngp.UUCP (Robert Dorsett) writes: > > Is there anything wrong with formatting disks labeled as single-sided as > > double-sided? I just upgraded to a Mac Plus and the manual says, quite > > explicitely, "Do NOT" format single-sided disks as double-sided disks. > > Sure you can go ahead and format single-sided diskettes as double-sided. > *****You run the risk of losing data****** > > Single sided diskettes are validated on one side only. Double sided are > validated on both. > > By saving a few bucks by using single sided diskettes as double, you may > lose important data. You do not know when, or even if, but why take a chance > for such little savings???? Just to add my own contribution to this discussion... I have been faithfully using Single sided disks for Double sided data ever since I got my upgrade (1 year). I know that the general feeling among those "in the industry" is to warn you away from trying to use a SS disk for 800K. I am sure they have their reasons, but I have never run into a problem, and since they use the SAME material to make single AND double sided disks, depending on which "basket" it falls into, I don't think the chances are very good that I ever will. The thing I am wondering about is that if they don't actually verify both sides of the disk, and later decide which way they are going to WARRANTY them to sell them as SS or DS. Well, enough from me... - Alan 'Don't worry about doing the right thing. Just never knowingly do the wrong thing.' - John Stakely
cds@duke.cs.duke.edu (Craig D. Singer) (06/11/87)
So SS disks are just like DS disks except that the other side has not been tested by the manufacturer, and using SS disks as DS disks risks losing data to a bad "other side." Ok, but what about the disk verifiers that come with some disk utility packages? Do these things do the same testing as the manufacturer? If so, there's a cheap solution to saving money on disks without risk. If the disk verifiers don't do what the manufacturers do, would some well-informed soul care to describe the differences? -- Craig D. Singer ARPA: cds@cs.duke.edu Department of Computer Science UUCP: ...!decvax!duke!cds Duke University CSNET: cds@duke Durham, NC 27706-2591 USA Phone (919) 684-5110 ext. 20
han@apple.UUCP (06/12/87)
In article <9766@duke.cs.duke.edu>, cds@duke.cs.duke.edu (Craig D. Singer) writes: > > So SS disks are just like DS disks except that the other side has not been > tested by the manufacturer, and using SS disks as DS disks risks losing data > to a bad "other side." > Nope - you lose data on any one side of a DS disk and you usually lose the whole disk, unless you've got some recovery tools and then it is only a maybe on recovering some of the data. The gist of the situations is as follows: It is foolish to save a couple of bucks per case of diskettes to use single sided instead of double sided. granted no disks are perfect, but why take risks unnecessarily? After all, backups are made only after data is lost, right? :-). ===================================================================== Byron Han | UUCP: {sun,voder,nsc,mtxinu,dual}!apple!han Apple Computer, Inc. | CSNET: han@apple.csnet 20525 Mariani Ave, | ATTNet: 408-973-6450 Cupertino, CA 95014 | GENIE: BYRONHAN APPLELINK: HAN1 MS 27Y | CSERVE: 72167,1664 ===================================================================== All opinions and statements do not necessarily represent those of my employer, Apple Computer Inc. =====================================================================
jww@sdcsvax.UCSD.EDU (Joel West) (06/12/87)
ComputerWare in Palo Alto has Sony 3.5" disks, double-sided.
If you buy 50 white disks ("bulk packed"), they're $1.50 each.
That's a pretty reasonable price, and where I always get mine.
I have no financial connection, etc., etc....
--
Joel West
{ucbvax,ihnp4}!sdcsvax!jww or jww@sdcsvax.ucsd.edufaulkner@scdpyr.UUCP (Bill Faulkner) (06/12/87)
There has been much disccussion lately about using SS disks as DS disks. It reminds me a lot about people trying to be cheap with memory and using 200ns memory instead of 150ns memory chips. Basiclly when you purchase a SS disk (or 200ns memory) the manufacture will guarentee it for its rated capacity only. About 90% of the time, one can use it as a DS with absolutely no problem. The other 10% is what you should be worried about. A DS disk (or 150 ns memory) will work at the higher rate (except in rare cases when the manufacture will replace it free). The only real difference between SS and DS disks (or 200ns and 150ns memory) is that the manufacturer has verified both sides of the DS disk as being good. The SS disk is usually identical to the DS, except that one side did not pass the DS test. This is similar to the memory situation where a single batch of chips, using the same mask, can contain 200ns chips, 150 ns chips, and 120ns chips. The chips are tested and the ones that pass certain speed tests are rated higher. In other words, The SS disks are actually rejects of double sided disks (well maybe not all of them, but if a proposed DS disk fails verification on the right side and the other side passes the manufacture will sell it as SS.) Now I have used SS as DS disks with little problem. However, it is used for transporting data that I can easily restore. I do not trust SS disk used as DS disks for anything I can't get an easy copy of. Therfore, those of you who want to save $.25 a disk, go ahead and buy SS disks, but don't come crying to the manufacturer when you lose data. I do suggest that you buy and use DS disks for any data you don't wish to lose (it's not guarenteed 100% save, but is a lot safer than SS disks). I will guarentee you that I will only use high quality DS disks for the back up of my hard disk. It isn't worth the risk to use my old SS disks as backups. A quick note about the verify option on several disk utilities. These routines are now where as thourgh as the disk manufacturers use. They are similiar but are single pass (i.e. reads and/or writes each track once) where as the manufacturer will read and write maybe 100 times. The verify option of these disk utilties are designed to allow you to verify that you have a problem with a specific disk (i.e. the mac won't copy some documents onto a disk that has plenty of space). You can then run the verify and see if the disk has an error, if so you can try to reformat the disk, thus eliminating the error. They are not designed for verifying that the disk media itself is alright. In summary, go ahead and use SS as DS, but if you care about the data you are storing, use DS. faulkner -- Bill Faulkner * NCAR (Nat'l Center for Atmospheric Research) PO Box 3000 * Boulder, CO 80307-3000 * 303-497-1259 UUCP: faulkner@scdpyr.UUCP or ..!hao!scdpyr!faulkner INTERNET: faulkner@scdpyr.ucar.edu ARPA: faulkner%ncar@csnet-relay.arpa
briand@tekig4.TEK.COM (Brian Diehm) (06/12/87)
>The gist of the situations is as follows: It is foolish to save a couple >of bucks per case of diskettes to use single sided instead of double sided. This discussion has been going on for a while now, and I can't stand it any more. First Statement: I ALWAYS back up my data on a second floppy. (Disclaimer: I don't back up my hard drive often enough to be safe, but that is another topic :-) If I am writing a document, every save is done on two different disks. Second Statement: I have used both sides of single-sided disks since they first came out 1.5 years ago. Third Statement: I have had a few single-sided disks not format as double. I do not use these. Fourth Statement: I have not had ANY floppy failure in the last 2 years. Given this kind of environment, why should I worry about it? If the risk of losing data is increased, it means to me that my risk of acutally NEEDING my backup is increased. The statements made by the manufacturers are correct. BUT - if you don't make backup copies, you are flirting disaster regardless of the disk certification. The key is the discipline implied in the statement "If I am writing a document, every save is done on two different disks." Without that discipline, you're on thin ice. With it, you are only increasing the risk of needing the backup, and that is a slight risk in my experience. -- -Brian Diehm (SDA - Standard Disclaimers Apply) Tektronix, Inc. briand@tekig4.TEK.COM or {decvax,cae780,uw-beaver}!tektronix!tekig4!briand
jl@well.UUCP (John Leininger) (06/13/87)
I was told by folks in the disk industry that when making ds disk both sides are verified. If one side passes and the other fails that will be put into a ss box. But when verifying ss only one side is verivied if it fails than the other side is tested and if it passes it is packed as ss. so you can get a ss disk that is just like a dd except that one side did not verify or that it was not verified. It is also my understanding that verification is much less tolerant than the drives that use the disks. I have been using ss disk as ds ever since the 800k drives came out and have had very few that would not format and none that lost data. floppies are perhaps the most durable items in the entire system after the power cords.
waltervj@dartvax.UUCP (walter jeffries) (06/15/87)
---
A little statistics... (from my own experiments)
Technique: I initialize disks three times as they are tested during
initialization this seems a reasonable trial. Those that fail any
pass are eliminated and the testing continues with the remaining disks.
I have been using this technique for over a year now and on over four
hundred diskettes. I buy almost exclusively Sony but I have also done
this test on BASF Double Sided(!) diskettes at work (I didn't even trust
the double sided ones to work as double sided...)
Results:
Sony's:
Sample size: 367 used single sided diskettes initialized as double sided
(mix of blue and beige colored diskettes some old, some ~new.)
Pass 1 -> 17 failures -> 5%
Pass 2 -> 5 failures -> 1%
Pass 3 -> 0 failures -> 0%
Total = 6% fail when ss used as ds
Long term (~1 year) three diskette failed later. Causes may have been
anything so it may or may not be significant.
BASF's:
Sample size: 50 fresh double sided diskettes initialized as double sided
Pass 1 -> 5 failures -> 10%
Pass 2 -> 4 failures -> 8%
Pass 3 -> 0 failures -> 0%
Total = 18% fail when ds used as ss
"Long" term 1 week zero diskette failed later. The reason I did this
with the ds BASF's was that my experience with ss BASF's was horrible.
A 18% failure rate for what they're supposed to be used for is pretty
bad. That's why I stick to Sony unless forced to use others as I am
at work.
-Walter Vose Jeffries, waltervj@dartvax (in real life).sl@van-bc.UUCP (Stuart Lynne) (06/15/87)
In article <1029@zog.cs.cmu.edu> tgl@zog.cs.cmu.edu (Tom Lane) writes: >>Is there anything wrong with formatting disks labeled as single-sided as >>double-sided? > >This seems to come up every 3 months on this newsgroup. The official >line is, as you say, that the back side of a SS disk is not tested. >It might be OK, then again, it might not. In this situation about all >you have to go on is anecdotal evidence, so here's my $0.02 worth: >I did it ONCE and got BURNT. This was three or so years ago when DS >3.5" drives were first becoming available. The disks in question were >Hewlett-Packard disks, which are made for HP by Sony; Sony has the >reputation of being the best brand of disk (see postings in this group >a couple of months back concerning independent tests). So it wasn't a >case of cheap off-brand disks. > I've never paid any attention to these warnings. At one point I even recycled about forty old Lisa Workshop distribution disks. Most of them formatted and worked ok. I find that perhaps one disk in ten just won't format. So I guess the formatting routines do a fair amount of checking. Anyway I either toss these ones or use them single sided. For disks that will see a fair amount of use, I at least try and start with a new disk (SS). For backup I just recycle whatever is around, using new ones if I don't have any old ones. The bottom line is the Mac software does seem to be pretty good at finding bad spots either during formatting or when writing. So far (touch wood) I havn't had any problems. (And I was about the second person to get an external double sided drive for my Mac 512k in Vancouver :-). Of course now that I have a hard disk I very rarely use floppies for anything other than backup. -- Stuart Lynne ihnp4!alberta!ubc-vision!van-bc!sl Vancouver,BC,604-937-7532
john@felix.UUCP (John Gilbert) (06/16/87)
In article <1010@apple.UUCP> han@apple.UUCP (Byron Han) writes: >In article <9766@duke.cs.duke.edu>, cds@duke.cs.duke.edu (Craig D. Singer) >writes: >> >> So SS disks are just like DS disks except that the other side has not been >> tested by the manufacturer, and using SS disks as DS disks risks losing data >> to a bad "other side." >> >Nope - you lose data on any one side of a DS disk and you usually lose the >whole disk, unless you've got some recovery tools and then it is only a maybe >on recovering some of the data. > I think you both said about the same thing. >The gist of the situations is as follows: It is foolish to save a couple >of bucks per case of diskettes to use single sided instead of double sided. > Well, where I buy disks, the difference is 16.99 for 15 SS, and 25.99 for 15 DS. That's 52% more for DS. Now, I look around my mac and I see a LOT of disks here. I am not advocating the use of SS as DS, but I wanted to point out that I seem to have more than a "few bucks" extra invested in the DS variety. Way more. -- John Gilbert .!trwrb!felix!john
ostroff@oswego.UUCP (Boyd Ostroff ) (06/17/87)
In article <983@killer.UUCP> perry@killer.UUCP (Alan Perry) writes: >In article <948@apple.UUCP>, han@apple.UUCP (Byron Han) writes: >> In article <5352@ut-ngp.UUCP>, mentat@ut-ngp.UUCP (Robert Dorsett) writes: >> > Is there anything wrong with formatting disks labeled as single-sided as >> > double-sided? I just upgraded to a Mac Plus and the manual says, quite >> > explicitely, "Do NOT" format single-sided disks as double-sided disks. ....etc.... >Just to add my own contribution to this discussion... > > I have been faithfully using Single sided disks for Double sided data ever >since I got my upgrade (1 year). I know that the general feeling among those > ...etc... Just to add my two bits to the discussion... We purchased a quantity of Fuji MF1DD (single-sided) disks here at SUNY on State contract before we upgraded our machine. Our experience here, as well as with my system at home is that we have about a 30% to 40% failure rate of these disks when formatted as double-sided. To my knowledge we have not had any failures of the same disk when formatting single-sided, so we only use these disks at 400K now. I primarily use hard-disk based systems and I've decided that the few pennies saved in buying the SS disks doesn't justify taking any higher risk, since I use floppies mainly for backups. If you MUST use SS disks, then my experience would _strongly_ suggest a strict backup regimen. We have wondered if, in fact, the SS disks are the ones which *failed* the DS certification... -- UUCP: seismo!rochester!rocksvax!oswego!ostroff US MAIL: Boyd Ostroff, Technical Director, Department of Theatre SUNY College at Oswego, Oswego, NY 13126 PHONE: (315) 341-2138
olson@batcomputer.UUCP (06/17/87)
In article <1010@apple.UUCP> han@apple.UUCP (Byron Han) writes: >The gist of the situations is as follows: It is foolish to save a couple >of bucks per case of diskettes to use single sided instead of double sided. True. When I buy new disks I get DS. Yet what about the 100 odd SSdisks I bought before there were any DSdisks. It would be nice to know which I could squeeze more stuff on to. In this case the savings are more then a few bucks per case ... :-) Todd Olson ARPA: olson@lasspvax.tn.cornell.edu ----- or ---- ARPA: olson@tcgould.tn.cornell.edu UUCP: {ihnp4,allegra,...}!cornell!lasspvax!olson US Mail: Dept Physics, Clark Hall, Cornell University, Ithaca, New York 14853-2501
russ@oakhill.UUCP (Russell Schwausch) (06/19/87)
Reply To: russ@oakhill.UUCP (Russell Schwausch)
Distribution: world
Organization: Motorola Inc. Austin, Tx
Keywords: Cautious but Poor
My experience using Maxell single-sided disks as double-sided disks
has been no failures on over 100 disks.
I tried a box of Sony single=sided disks and one disk
failed so I went back to Maxell. My source sells Maxell SS for $9.95 and
Maxell DS for $16.95 and for the difference in price I am willing to
take the risk. I make sure important programs and data are backed up on
at least two different disks. I think the risk of putting a disk next to
a magnetic field or pouring a softdrink on it or crunching it are greater
than the risk of it just deciding to fail because it started out single-sided.
This isn't for everyone and I wouldn't do it in a business environment.
I am just trying to squeeze every nickel I can out of my computer, my software,
and my diskettes.
Let the user beware!!!!!!!!!
--
Russell Schwausch, Motorola Inc., OakHill, Tx. (A suburb of Austin)
UUCP: {harvard,ihnp4,seismo,gatech,nbires}..!ut-sally!oakhill!russ
Ma Bell: (512)440-2426
It's a ticket agent, it's a fare collector, no ... it's SUPERCONDUCTOR!!!