phil@diablo.amd.com (07/11/89)
I just ran an experiment with double sided 3 1/2 in floppies. On one,
I melted a hole in the corner with a soldering iron. On another, I
cut the entire corner off and then resealed it with a soldering iron.
I then tried formatting as 1.44 Mb floppies -- it worked!
This information is offered as is, with no warranty of merchantability
or fitness for any particular use nor any other warranty, express or
implied, as to the accuracy of the enclosed materials or suitability
for any particular purpose.
--
Phil Ngai, phil@diablo.amd.com {uunet,decwrl,ucbvax}!amdcad!phil
"The government is not your mother."ken@cs.rochester.edu (Ken Yap) (07/11/89)
Another method that was posted in a PC mag is to defeat the microswitch inside the drive that detects the floppy casing type. This way you don't have to punch a lot of floppies. Info offered as is. Not responsible for consequences.
ching@pepsi.amd.com (Mike Ching) (07/11/89)
In article <26260@amdcad.AMD.COM> phil@diablo.amd.com () writes: > >I just ran an experiment with double sided 3 1/2 in floppies. On one, >I melted a hole in the corner with a soldering iron. On another, I >cut the entire corner off and then resealed it with a soldering iron. > >I then tried formatting as 1.44 Mb floppies -- it worked! > Anyone know how the 1.44Mb floppies achieve the density? More tracks? More sectors/track? *Should* this work? You can't use 360K 5 1/4" floppies at 1.2M because the coercivity of the coating is different but you can make them 720K by doubling the number of tracks. So how do 1.44M floppies differ from 720K ones besides the hole? mike ching
genemans@eleazar.dartmouth.edu (Jan Genemans) (07/11/89)
In article <26262@amdcad.AMD.COM> ching@pepsi.AMD.COM (Mike Ching) writes: >In article <26260@amdcad.AMD.COM> phil@diablo.amd.com writes: >> >>I just ran an experiment with double sided 3 1/2 in floppies. On one, >>I melted a hole in the corner with a soldering iron. On another, I >>cut the entire corner off and then resealed it with a soldering iron. >> >>I then tried formatting as 1.44 Mb floppies -- it worked! >> >Anyone know how the 1.44Mb floppies achieve the density? More tracks? >More sectors/track? *Should* this work? You can't use 360K 5 1/4" >floppies at 1.2M because the coercivity of the coating is different but >you can make them 720K by doubling the number of tracks. If anyone is going to try this, they should be forwarned. I have used ~500 disks in the 720k format with only 2 failures. However, when I converted the disks into 1.44M with soldering a hole in them roughly one out of five disks had a failure, thus a ~5000% increase in disk failures. If you insist on modifying the disks to a higher density than rated make sure that you backup *everything* or you might loose valuable data. As for the 5.25" DS/DD format- ted as 1.2M DS/HD I had a failure rate of 50% or 5 out of 10 disk attempts. Other people might have different results, however, I strongly advise that this should not be done because of the headache of loosing data, even if it backed up. I suspect that the "coercivity of the coating" is different for the 1.44M as well as the 1.2M in comparison to the lower density disks. / Jan Genemans | USENET: Jan.Genemans@Dartmouth.edu \ / Engineering Dept | UUCP: ...!dartvax!mac.dartmouth.edu!Jan.Genemans \ \ U.S.M.M.A. +---------+------------------------------------------/ \ Kings Point, NY 11024 | "Live long and prosper" -Spock /
russ@hp-lsd.HP.COM (Russell Johnston) (07/11/89)
I saw an ad in PC WORLD (June 1989, page 16) from Biological Engineering, Inc for a product called DoubleDisk Converter they claim will allow formatting a 'low density' 3.5" diskette to 1.44MB. They have a money back guarantee, and offer to replace any diskette that does not format with a name brand high density diskette. Has anyone tried this product, or know what their technique is? The price is $39.95 + 3.50 shipping (2.40 CA tax), 800/537-4226.
kent@sun.ufnet.ufl.edu (Kent Phelps) (07/12/89)
In article <26260@amdcad.AMD.COM> phil@diablo.amd.com () writes: > >I just ran an experiment with double sided 3 1/2 in floppies. On one, >I melted a hole in the corner with a soldering iron. On another, I >cut the entire corner off and then resealed it with a soldering iron. > >I then tried formatting as 1.44 Mb floppies -- it worked! > >This information is offered as is, with no warranty of merchantability >or fitness for any particular use nor any other warranty, express or >implied, as to the accuracy of the enclosed materials or suitability >for any particular purpose. > >-- >Phil Ngai, phil@diablo.amd.com {uunet,decwrl,ucbvax}!amdcad!phil >"The government is not your mother." Ahhh- here we go again with this subject. I DO NOT suggest using this procedure. I have seen disks formatted in this manner lose data just sitting on the shelf. I know there are MANY, MANY so-called experts that will swear that this procedure is fine and safe. I repeat- IT IS NOT. I have seen it fail over and over. Use at your own risk ( or your data's) -- Kent Phelps | Internet: kent@sun.ufnet.ufl.edu University of Florida | UUCP: ... ???? Digital Design Facility| Phone: 904-335-8322
wnp@attctc.DALLAS.TX.US (Wolf Paul) (07/12/89)
In article <26262@amdcad.AMD.COM> ching@pepsi.AMD.COM (Mike Ching) writes: >Anyone know how the 1.44Mb floppies achieve the density? More tracks? >More sectors/track? *Should* this work? You can't use 360K 5 1/4" >floppies at 1.2M because the coercivity of the coating is different but >you can make them 720K by doubling the number of tracks. > >So how do 1.44M floppies differ from 720K ones besides the hole? I don't know the difference in magnetic property of the medium, but as far as formatting under DOS and other PC operating systems (UNIX, XENIX) is concerned, 1.44M floppies are formatted with 80 tracks of 18 sectors each. In fact, to be complete, here is a list of track/sector configurations for most common PC disk formats: Capacity Tracks Sec/Track 320K 40 8 360K 40 9 400K 40 10 Notes 1, 2 720K 80 9 Note 3 800K 80 10 Note 2 1.2M 80 15 1.44M 80 18 Notes: 1. This is the AT&T UNIX PC native format; 2. There are a couple pd format programs which format double-density diskettes to 400K (XT-style drives) or 800K (AT-style or older 96TPI drives), also 3.5" 720k drives); 3. Both 5.25" and 3.5" drives use the same format; Hope this information is helpful. -- Wolf N. Paul * 3387 Sam Rayburn Run * Carrollton TX 75007 * (214) 306-9101 UUCP: {texbell, attctc, dalsqnt}!dcs!wnp DOMAIN: wnp@attctc.dallas.tx.us or wnp%dcs@texbell.swbt.com NOTICE: As of July 3, 1989, "killer" has become "attctc".
werner@aecom.yu.edu (Craig Werner) (07/12/89)
I was already to be faced with this dilemma when I discovered that
the Mitsubishi drives that come in my Wells American CompuStar do not
seem to check. They will take an MF-2 DS/2D and format it for 80 tracks
(1.44M) -- No questions asked. They do however, seem to place the wrong
number of bytes on the disk (1467496, I think VS 1461248, about 6K extra)
unless you specify T:80, but they do this even on the correct HD medium.
I have been told that this is not the drive's fault, but rather the way
PC-DOS format mishandles external 3.5" drives. Anyway, the former saves
big bucks, while the latter just costs a few extra letters on the command line.
--
Craig Werner (future MD/PhD, 4.5 years down, 2.5 to go)
werner@aecom.YU.EDU -- Albert Einstein College of Medicine
(1935-14E Eastchester Rd., Bronx NY 10461, 212-931-2517)
"If I don't see you soon, I'll see you later."phil@diablo.amd.com (Phil Ngai) (07/14/89)
In article <8020020@hp-lsd.HP.COM> russ@hp-lsd.HP.COM (Russell Johnston) writes: |I saw an ad in PC WORLD (June 1989, page 16) from Biological Engineering, Inc |for a product called DoubleDisk Converter they claim will allow formatting |a 'low density' 3.5" diskette to 1.44MB. They have a money back guarantee, |and offer to replace any diskette that does not format with a name brand |high density diskette. Has anyone tried this product, or know what their |technique is? The price is $39.95 + 3.50 shipping (2.40 CA tax), 800/537-4226. I bet a nickel it punches a hole in the corner of the diskette cover. -- Phil Ngai, phil@diablo.amd.com {uunet,decwrl,ucbvax}!amdcad!phil "The government is not your mother."
soley@moegate.UUCP (Norman S. Soley) (07/14/89)
In article <8020020@hp-lsd.HP.COM> russ@hp-lsd.HP.COM (Russell Johnston) writes: >I saw an ad in PC WORLD (June 1989, page 16) from Biological Engineering, Inc >for a product called DoubleDisk Converter they claim will allow formatting >and offer to replace any diskette that does not format with a name brand >high density diskette. Has anyone tried this product, or know what their >technique is? The price is $39.95 + 3.50 shipping (2.40 CA tax), 800/537-4226. 1.44 diskettes have an extra hole punched through the plastic case somewhere. Many PCs (IBM and Compaq, for two) have convieniently omitted or disconnected the sensor (In my T3100e it "works"). All the DoubleDisk Converter does is punch that hole. The maker is not guarenteeing that the DD disk will format to full 1.44 Meg capacity, only that it will format (which it most certianly will do). If you own an IBM or a Compaq don't bother with this thing. Personally I wouldn't much trust a disk formatted this way anyway. -- Norman Soley - The Communications Guy - Ontario Ministry of the Environment soley@moegate.UUCP or if you roll your own: uunet!attcan!ncrcan!moegate!soley The Minister speaks for the Ministry, I speak for myself. Got that! Good. Head for the hills - The shriners are coming, the shriners are coming
wnp@attctc.DALLAS.TX.US (Wolf Paul) (07/14/89)
In article <8020020@hp-lsd.HP.COM> russ@hp-lsd.HP.COM (Russell Johnston) writes: >I saw an ad in PC WORLD (June 1989, page 16) from Biological Engineering, Inc >for a product called DoubleDisk Converter they claim will allow formatting >a 'low density' 3.5" diskette to 1.44MB. They have a money back guarantee, >and offer to replace any diskette that does not format with a name brand >high density diskette. Has anyone tried this product, or know what their >technique is? The price is $39.95 + 3.50 shipping (2.40 CA tax), 800/537-4226. I have their DoubleDisk converter. It is simply a hole punch which holds your 3.5" disk in place so the hole gets put in the right place, opposite the write-protect hole. I have found that most of the 720K disks I purchased from MEI Micro work just fine as 1.44M after punching the hole; the only problems I have seen is the fact that some of the disks are encased in more brittle plastic than others. Brittle plastic does not take too kindly to having holes punched in it; it cracks. But the disks still work, although I would not leave them lying in the spilt coffee for too long :-) Alternative propositions I have seen suggest burning a round hole in the disk with a soldering iron; that should work too, provided the hole is in the right place. Also, on some 1.44M drives, it is possible to disable the sensor which distinguishes between the two types of disks. Then you have to use driver.sys or the equivalent to tell format how to format the diskettes. I would be very much interested in a discussion of the magnetic properties of 360K, 1.2M, 720K and 1.44M diskettes, respectively. Apparently, the surface difference between double and high density 3.5" diskettes is NOT THE SAME as the difference between double and high density 5.25" disks. -- Wolf N. Paul * 3387 Sam Rayburn Run * Carrollton TX 75007 * (214) 306-9101 UUCP: {texbell, attctc, dalsqnt}!dcs!wnp DOMAIN: wnp@attctc.dallas.tx.us or wnp%dcs@texbell.swbt.com NOTICE: As of July 3, 1989, "killer" has become "attctc".
hjg@amms4.UUCP (Harry Gross) (07/15/89)
In article <14333@dartvax.Dartmouth.EDU> genemans@mac.dartmouth.edu (Jan Genemans) writes: [stuff deleted regarding turning 760K's into 1.44M's] >If anyone is going to try this, they should be forwarned. I have used ~500 >disks in the 720k format with only 2 failures. However, when I converted the >disks into 1.44M with soldering a hole in them roughly one out of five disks >had a failure, thus a ~5000% increase in disk failures. If you insist on >modifying the disks to a higher density than rated make sure that you backup >*everything* or you might loose valuable data. As for the 5.25" DS/DD format- >ted as 1.2M DS/HD I had a failure rate of 50% or 5 out of 10 disk attempts. >Other people might have different results, however, I strongly advise that >this should not be done because of the headache of loosing data, even if it >backed up. > >I suspect that the "coercivity of the coating" is different for the 1.44M as >well as the 1.2M in comparison to the lower density disks. I posted something on this a few minutes ago. As far as I have been able to determine, the only difference between the two diskettes it the use of the flip side for data storage. In all probability, the second side is perfectly fine to use. HOWEVER, there are no guarantees that the coating is 'computer grade' on the flip side of a 720K diskette. Most of the time, though, it works. This 'trick' used to be used on CP/M (remember that? :-) systems to get double sided diskettes out of single sided ones. Sometimes, the second side didn't have a coating at all. Also, just as someone came out with a tool for notching a 5 1/4" floppy so that you could flip it over and use the other side (like in an Apple, for example, which ONLY has single sided drives), i have seen a tool advertised in PC-MAGAZINE for punching out the necessary hole. Using a soldering iron is risky, as the excessive heat could damage the disk itself. Also, just punching a hole could leave little bits of plastic floating around. The tool perportedly avoids those problems. Cheers -- Harry Gross | reserved for | something really Internet: hjg@amms4.UUCP (we're working on registering)| clever - any UUCP: {jyacc, rna, bklyncis}!amms4!hjg | suggestions?
wnp@attctc.DALLAS.TX.US (Wolf Paul) (07/16/89)
In article <563@amms4.UUCP> hjg@amms4.UUCP (Harry Gross) writes: (regarding the difference between 720K and 1.44M 3.5" disks) >I posted something on this a few minutes ago. As far as I have been able to >determine, the only difference between the two diskettes it the use of the >flip side for data storage. In all probability, the second side is perfectly >fine to use. HOWEVER, there are no guarantees that the coating is 'computer >grade' on the flip side of a 720K disk. Most of the time, though, it works. I am afraid your information is wrong. Both 720K and 1.44M 3.5" diskettes used on PCs and 800K diskettes used on MACs are DOUBLESIDED disks. The only SINGLESIDED 3.5" format I am aware of is the older MAC 400K format (prior to the MAC Plus). The difference between 720K and 1.44M disks is not the number of sides used, but the number of 512-byte sectors written per track. 720K disks have 9 sectors per track, while 1.44M disks have 18 sectors per track. The question with regard to the 3.5" disk notchers is, what is responsible for the higher data density: just the design of the drives, or is the magnetic coating of the 1.4M disks different? All I have seen and heard on that subject so far are "guesses" -- nobody with facts. -- Wolf N. Paul * 3387 Sam Rayburn Run * Carrollton TX 75007 * (214) 306-9101 UUCP: {texbell, attctc, dalsqnt}!dcs!wnp DOMAIN: wnp@attctc.dallas.tx.us or wnp%dcs@texbell.swbt.com NOTICE: As of July 3, 1989, "killer" has become "attctc".
chao@cory.Berkeley.EDU (Chia-Chi Chao) (07/16/89)
In article <8663@attctc.DALLAS.TX.US> wnp@attctc.Dallas.TX.US (Wolf Paul) writes: >The question with regard to the 3.5" disk notchers is, what is responsible >for the higher data density: just the design of the drives, or is the >magnetic coating of the 1.4M disks different? All I have seen and heard >on that subject so far are "guesses" -- nobody with facts. There was an article here from Timothy Lange (35168 on 6/19/89) on all the different diskettes. Double density uses iron oxide, and high density uses chromium oxide. Magnetic coercivities are different.
nts0302@dsacg3.UUCP (Bob Fisher) (07/17/89)
From article <563@amms4.UUCP>, by hjg@amms4.UUCP (Harry Gross):
-> In article <14333@dartvax.Dartmouth.EDU> genemans@mac.dartmouth.edu (Jan Genemans) writes:
->
-> just as someone came out with a tool for notching a 5 1/4" floppy so that
-> you could flip it over and use the other side (like in an Apple, for example,
-> which ONLY has single sided drives), i have seen a tool advertised in
-> PC-MAGAZINE for punching out the necessary hole. Using a soldering iron is
-> risky, as the excessive heat could damage the disk itself. Also,just punching
-> a hole could leave little bits of plastic floating around. The tool perportedly
-> avoids those problems.
I used a plain round hole paper punch on an old Apple ][+. Worked great,
caught its own chips and didn't warp from the heat.
--
Bob Fisher (osu-cis!dsacg1!bfisher) 614-238-9071 (Autovon 850-9071)
From the Internet: bfisher%dsacg1.uucp@daitc.arpa
US Defense Logistics Agency Systems Automation Center
DSAC-TSX, Box 1605, Columbus, OH 43216-5002gwang@berlioz (George Wang) (07/18/89)
In article <8649@attctc.DALLAS.TX.US> wnp@attctc.Dallas.TX.US (Wolf Paul) writes: >I would be very much interested in a discussion of the magnetic properties >of 360K, 1.2M, 720K and 1.44M diskettes, respectively. Apparently, the >surface difference between double and high density 3.5" diskettes is NOT >THE SAME as the difference between double and high density 5.25" disks. > > Correction! There *IS* a difference in the magnetic media of 3.5 High Density and Low Density diskettes... If you examine the medias of NAME BRAND diskettes you will notice a visible difference in the media of low and high density 3.5 diskettes... Furthermore, high density drives write in a lower signal level than low densities... Perhaps bulk-quality disk companies who claim that there diskettes are high density certified are using the same "hole punch" trick... But Name brand diskette companies such as 3M produce diskettes that do *NOT* have the same media surfaces... The same difference exists in 5.25 diskettes... George Gwang@berlioz.nsc.com
gwang@berlioz (George Wang) (07/18/89)
In article <563@amms4.UUCP> hjg@amms4.UUCP (Harry Gross) writes: > >I posted something on this a few minutes ago. As far as I have been able to >determine, the only difference between the two diskettes it the use of the >flip side for data storage. In all probability, the second side is perfectly >fine to use. HOWEVER, there are no guarantees that the coating is 'computer >grade' on the flip side of a 720K diskette. Most of the time, though, it works. I think your understanding of the "flip" side concept arises from it's use in computers such as the APPLE II and NOT in IBM PC's.... The IBM PC *AUTOMATICALLY* uses both sides of a diskette... So the double capacity difference between the 720K and 1.44 Meg diskette is not the use of a "flip" side, nor the increase in the number of tracks... The increase is achieved through the higher sector per track density.... A 720K diskette has 9 sectors per track and a 1.44 meg diskette has 18 sectors per track... The talk of a "flip" side is out of date... These days everyone produces diskettes that have both sides coated with magnetic media.... Single sided 5.25 diskettes are not sold as such these days altough 3.5 single sided disks are (though they are being phased out too....) George Gwang@berlioz.nsc.com
markw@airgun.UUCP (Mark Whetzel) (07/18/89)
Adding to the discussion about using 3.5" floppies for 1.44 meg use when they are rated for '720K'. The only floppies our company uses are these disks. In fact our supply room does not stock anything else (only by special order can you get 1.44 meg disks). Out of over 100 boxes of disks that I have personally used I have not run across a single disk that did not format and operate properly. As the technical co-ordinator for my company, I have not received any complaints about format or usage problems with this policy with the rest of the ps2's that our company uses (approx 100 ps2's and growing). However, I do recommend to my users that if they have a critical backup that must be trouble free to use the 1.44meg floppies. (CYA) Luckly for us the IBM ps2's do not need the second hole to format the entire disk. -- Mark Whetzel My comments are my own, not my company's. Western Geophysical - A division of Western Atlas International, A Litton/Dresser Company ...!texbell!moray!airgun!markw UUNET address: uunet!airgun!markw
wnp@attctc.Dallas.TX.US (Wolf Paul) (07/18/89)
In article <435@berlioz.nsc.com> gwang@berlioz.UUCP (George Wang) writes: +In article <8649@attctc.DALLAS.TX.US> wnp@attctc.Dallas.TX.US (W. Paul) writes: + +>of 360K, 1.2M, 720K and 1.44M diskettes, respectively. Apparently, the +>surface difference between double and high density 3.5" diskettes is NOT +>THE SAME as the difference between double and high density 5.25" disks. +> +Correction! There *IS* a difference in the magnetic media of +3.5 High Density and Low Density diskettes... If you examine the +medias of NAME BRAND diskettes you will notice a visible difference +in the media of low and high density 3.5 diskettes... Furthermore, +high density drives write in a lower signal level than low +densities... + +are high density certified are using the same "hole punch" trick... +But Name brand diskette companies such as 3M produce diskettes +that do *NOT* have the same media surfaces... The same difference +exists in 5.25 diskettes... + Notice that I didn't say that there is NO difference between DD and HD 3.5" disks, but rather that it doesn't seem to be the same difference as between DD and HD 5.25" disks. If you dispute that, back it up with specific coercivity values, and tell me why I can use my hole punch on a DD 3.5" disk, and then format it to 1.44MB with NO BAD SECTORS, while I am UNABLE to format a DD 5.25" disk to 1.2MB. And I tried this on many different drives -- so don't tell me its my 5.25" drive. It's the media allright. And visual differences are pretty irrelevant -- they can be intentional, to mislead the user into thinking there is a difference. Its like diesel fuel in Europe -- non-taxed fuel for agricultural use is dyed differently from taxed fuel for road use, and the same diesel fuel for heating purposes is colored still differently. The only difference is the dye, and the price to the enduser. -- Wolf N. Paul * 3387 Sam Rayburn Run * Carrollton TX 75007 * (214) 306-9101 UUCP: {texbell, attctc, dalsqnt}!dcs!wnp DOMAIN: wnp@attctc.dallas.tx.us or wnp%dcs@texbell.swbt.com NOTICE: As of July 3, 1989, "killer" has become "attctc".
wtm@neoucom.UUCP (Bill Mayhew) (07/19/89)
I've seen that advert in the back of Byte too, where they take a whole page to descirbe a mysteious tool to convert single density 3-1/2 inch diskettes into high density. I'd imagine that the so-called tool is nothing more than a glorified hole punch to put in the keying notch for density sensing. Both 720K and HD diskettes have 80 tracks, double sided. The difference is that the HD diskettes have 18 sectors per track, while the 720K diskettes are 9 sector. I could see possibly using the notching tool to convert over diskettes for storing things like the operating copy of one's word processor, but I feel that it would be folly to trust the disks for storage of original data or 1st generation back-ups. Trusting a questionable disk to a back-up is escpecially silly. I know what it feels like to blow away an article that I am working on, then say "no sweat, I've got a back-up copy" only to find that the back-up is bad. For back-ups, I use good media and verify writes carefully before I put my back-ups away. I knew a guy that used to do the soldering iron trick to make HD disks, he had problems that the buggered disks wold work for a while then start to get soft and eventually hard errors. I get the 'luxury' on my PS/2-80 of having it mistakenly format everything as HD, ignoring the density. To properly format 720K disks, I have to remember to specify "FORMAT /N:9 A:", where N: is an option switch to specify 9 sectors. I'd be curious on hearing from people that have clone machines, if you can force a format to HD by typing "FORMAT /N:18". :-) By the way, I'm using genuine IBM DOS 3.3 on that machine. Bill
jcw@jwren.UUCP (John C. Wren) (07/23/89)
In article <1686@neoucom.UUCP> wtm@neoucom.UUCP (Bill Mayhew) writes: > > [ Stuff deleted ] > >I get the 'luxury' on my PS/2-80 of having it mistakenly format >everything as HD, ignoring the density. To properly format 720K >disks, I have to remember to specify "FORMAT /N:9 A:", where N: is >an option switch to specify 9 sectors. I'd be curious on hearing >from people that have clone machines, if you can force a format to >HD by typing "FORMAT /N:18". :-) By the way, I'm using genuine IBM >DOS 3.3 on that machine. > Ain't DOS's fault. Those miserable co-ops at IBM who design their machines apparently didn't read the instruction manual for the 3.5" drive, and total hosed-up the density sense line. I ordered a SYSGEN 3.5" external drive, set it up, shoved a diskette in, and formatted it. Lo and behold my 720K diskette now had 1.44mb on it, plus a lot of errors. I called to tell them I like to product, but why do the ignore the sense line? They said "we had to do it because IBM did it". I can understand their thinking. After all, when you come to expect certain behavior from a device, you have to replicate it. - John C. Wren jcw@jwren