mfrohman@digi.lonestar.org (Matthew Frohman) (07/19/90)
I have a pair of those floppy drives which insists on detecting for me, if there is a hole in my floppy disk. I would like to install a toggle switch to enable/disable the detector. Ideally, I would like it to have 3 positions: HD, LD, or auto detect, but I don't know if that is possible. Simply having 2 position (detect, no detect) would be sufficient. I need this because I have disks formatted at 720K for my laptop that my PC insists are HD, since they have a hole in them, so I cannot write info to that disk on my PC without scrambling the FAT. Anyone out there done this already? A detailed description would be appreciated, since I do not do this sort of thing often, and I don't want to destroy my computer. BTW. I have a HD 5 1/4 and a HD 3 1/2, but I really want this for the 3 1/2, though I would thing it would be the same process for both. Thanks in advance, Matthew
ezk@cunixe.cc.columbia.edu (Erez "HWank1" Zadok) (07/20/90)
In article <803@digi.lonestar.org> mfrohman@digi.lonestar.org (Matthew Frohman) writes: > I have a pair of those floppy drives which insists on detecting for me, > if there is a hole in my floppy disk. I would like to install a toggle > switch to enable/disable the detector. Ideally, I would like it to have [...] > Anyone out there done this already? A detailed description would be > appreciated, since I do not do this sort of thing often, and I don't > want to destroy my computer. [...] > Thanks in advance, > Matthew A while back I was seeking a software solution to the same problem, via the DRIVPARM option of CONFIG.SYS. I dumped the idea and decided to (finally :-) utilize my 5 years of EE studies and put a switch instead. I opened my machine and after a few screws (no jokes please) got to the circuit board of my 3.5 drive (I think it is a Mitsubishi) where I found a small switch on the front right corner of the board. I soldered out that switch. Put a hole in the left front panel of my drive and made sure the location of the external switch did not interfere with anything inside. I then placed a simple two-position on/off switch where I made the hole, and ran two 22 gauge wires from the external switch to the previous location of the internal switch. You have to make sure the wires you run don't interfere with the moving parts inside the drive. Of course I could have put the switch on the right side, or anywhere else on my box. That's your choice. If your drive is of a different make, the instructions may vary. The location of the screws may be different, etc. Now, if the external switch is in one position, I can read and format DD disks, and if it's in the other position, I can read DD or HD and format HD. I found that to be most convenient esp. when you're short on disk space. I haven't had any problems since (5-6 weeks now.) Note however that formatting as HD on a DD disk might not yield a full 1.44Mb and should not be used for long term storage of files since these disks tend to go bad often; but for short periods of time formatting DD as HD is fine. I would guess that there might be a way to have a switch that would also have an "auto sense" mode, but I didn't really want to complicate matters too much. I found the current setup adequate. After I format my floppies, I put the switch in the one mode that can read both HD and DD. Hope this helps. Erez. A wank's morning starts one machine | Arpa: ezk@cunixf.cc.columbia.edu clock cycle after midnight. | Usenet: ...!rutgers!columbia!cunixf!ezk -HebrewWank #1 (US meaning, not UK!) | Bitnet: ezk@cunixf, erzus@cuvmb
grege@gold.GVG.TEK.COM (Greg Ebert) (07/20/90)
I've been tinkering with a 3.5" drive, and although there is a signal which the drive generates based upon the type of disk (720/1.44M), it seems to be unconnected (hence ignored) by the floppy controller, as far as I can remember. Thus, I don't think a toggle switch will solve your problem. The difference between 720K and 1.44M formatted diskettes is single vs. double density, and not narrower tracks as in 1.2M floppy drives. All 5.25" drives are asumed to be double density. My MSDOS technical information regarding FATs, etc is a bit outdated, but it does describe single and double-density 8" diskette support. Basically, an attempt is made to read the disk in single density. If a read-error occurs, an attempt will be made using double density. I conclude that it is a BIOS constraint whether your 3.5" drive is 720K or 1.44M. Any BIOS gurus out there wish to comment ?
tindle@ms.uky.edu (Dan Chaney) (07/20/90)
For those not into hacking with an iron, one can (of course) buy a commercial product- Most aftermarket 3.5" HD drives can be set by jumper to either pay attention to the sensor hole, or to pay attention to the DENSITY SELECT line. The drives come set for the sensor active, because most floppy controllers don't do anything with D.S. Micro Solutions CompatiCard IV, along with its included CC4DRV.SYS, will sense what kind of disk you have and adjust itself, IF your drive jumpers are set to ignore sensor. Works very well; we have two in the lab here. Micro Solutions has a real winner with the CompatiCard IV- you can connect up to four drives inside, with one external; it handles 8" to 2.8Mb format, auto-boot from *any* connected floppy, support for dual speed 5.25" HD drives, support for cross-formatted 3.5" disks, and formatting disks in the background while other programs are running. Micro Solutions can be reached at (815) 756-3411. I have no connection with them except as a satisfied customer. --------------------------\ /----------------------------------------------- INTERNET:tindle@ms.uky.edu | "Could you please continue the petty bickering? BITNET: tindle@ukma.bitnet | I find it most intriguing." --- Data, Ken Tindle - Lexington, KY | Star Trek, The Next Generation, "Haven" --------------------------/ \-----------------------------------------------
ih@udel.edu (Charlie Ih) (07/20/90)
In article <1990Jul19.193954.29829@cunixf.cc.columbia.edu> ezk@cunixe.cc.columbia.edu (Erez "HWank1" Zadok) writes: >In article <803@digi.lonestar.org> mfrohman@digi.lonestar.org (Matthew Frohman) writes: ..... >:-) utilize my 5 years of EE studies and put a switch instead. I opened my >machine and after a few screws (no jokes please) got to the circuit board of >my 3.5 drive (I think it is a Mitsubishi) where I found a small switch on >the front right corner of the board. I soldered out that switch. Put a >hole in the left front panel of my drive and made sure the location of the >external switch did not interfere with anything inside. ..... > >Hope this helps. > >Erez. The information is very helpful to others as well. I hope we can have more of this kind information to help each other. Congratulations and thanks. Just curious, why could you just leave the switch there (in open position) and connect the "external" switch in parallel with it? This would require less work but more important have less chance to damage the circuit board. Since I don't know the actual situation, maybe the removal of the switch was necessary. Thanks again! Charles S. Ih
kevin@msa3b.UUCP (Kevin P. Kleinfelter) (07/20/90)
mfrohman@digi.lonestar.org (Matthew Frohman) writes: >I have a pair of those floppy drives which insists on detecting for me, >if there is a hole in my floppy disk. I would like to install a toggle >switch to enable/disable the detector. Ideally, I would like it to have >3 positions: HD, LD, or auto detect, but I don't know if that is possible. >Simply having 2 position (detect, no detect) would be sufficient. I need >this because I have disks formatted at 720K for my laptop that my PC insists >are HD, since they have a hole in them, so I cannot write info to that disk >on my PC without scrambling the FAT. I have done this. It is relatively easy, if you know how to use a soldering iron. There are actually two different methods, depending on the drive. As one method is much easier, and does not require soldering, you should first determine which method will work for you. Based on what you have said above, your situation will probably require "Method B". Get an HD diskette. You just need one for this test. Buy it or borrow it. Insert it in your desktop PC's floppy. Format it to 720K via format a: /N:9 /T:80 If this does not work, you must use "Method B" (described below). If this DOES work, then copy several text files to the disk. Then take the disk to your laptop and "type" those files. If it does not work, you must use "Method B". If it does work, copy several text files from the laptop TO this disk, and verify that you can read them on the desktop. ======================================================================= METHOD A: For use where the HD drive can treat an HD disk like an LD. This method CANNOT be used on systems that won't accept "format a: /N:9 /T:80" on an HD disk. 1. Remove the disk drive. 2. Locate the HD microswitch. This is a small switch with a little plastic piece that sticks up through the HD hole. If you are looking at the front of the drive, it is the switch on the RIGHT. (Don't mess with the switch on the left or all your disk just became write protected!) 3. There should be 2 wires running to this (most drives have 2 wires, but there could be a drive with one or connections directly soldered to a PCB). Cut either wire. Tape or otherwise put the wire end out of the way of the moving parts of the drive. 4. Reassemble. 5. Your machine now thinks that all disks are HD. I hope that your machine is willing to treat an HD disk as an LD disk if you tell it to do so. ======================================================================= ======================================================================= METHOD B: For use where the the system can't handle "format a: /T:80 /N:9". 1. Remove the disk drive. 2. Locate the HD microswitch. This is a small switch with a little plastic piece that sticks up through the HD hole. If you are looking at the front of the drive, it is the switch on the RIGHT. (Don't mess with the switch on the left or all your disk just became write protected!) 3. There should be 2 wires running to this (most drives have 2 wires, but there could be a drive with one or connections directly soldered to a PCB). Unsolder both wires from the switch. 4. Poke a hole through the front of the drive bezel, in a location where it will be out of harms way, but where both wires will reach. Use a drill or any other appropriate implement of destruction. 5. Insert a SPST switch in the hole, and solder the wires from the microswitch to this switch. 6. Reassemble. 7. With the switch in one position, you have an HD drive. In the other position, you have an LD drive. Experiment to determine which is which. ======================================================================= DISCLAIMER: I did both methods. It worked for me, but I cannot accept responsibility for melting your machine into oblivion. -- Kevin Kleinfelter @ Management Science America, Inc (404) 239-2347 gatech!nanovx!msa3b!kevin "Don't hold your finger on the button if the motor ain't goin' roundy-roundy."
ezk@cunixf.cc.columbia.edu (Erez "HWank1" Zadok) (07/21/90)
In article <25160@nigel.udel.EDU> ih@udel.edu (Charlie Ih) writes: > In article <1990Jul19.193954.29829@cunixf.cc.columbia.edu> ezk@cunixe.cc.columbia.edu (Erez "HWank1" Zadok) writes: > >In article <803@digi.lonestar.org> mfrohman@digi.lonestar.org (Matthew Frohman) writes: [...] > and thanks. Just curious, why could you just leave the switch there > (in open position) and connect the "external" switch in parallel with it? > This would require less work but more important have less chance to damage > the circuit board. Since I don't know the actual situation, maybe > the removal of the switch was necessary. Thanks again! > > Charles S. Ih I gather from your question that you're not familiar with basic electronics. That's ok. Here's an explanation I hope would make sense. First, if you've had some experience with soldering, you'd know that the faster you solder out the switch the better it is. I've had my share of heat-until-the-contacts-pop-off-the-board experience (you EE people *know* what I'm talking about.) Other than that, I see no possible harm to the circuit board. I could not have left the internal switch in open position b/c the minute I put a DD floppy inside (no 2nd hole) the internal switch would be pushed down, thus creating a short between the two points. Now, if I also have an external switch outside, which I wanted to set to the "open" position (force a break of the connection), then the internal switch being connected in parallel would override the external one and the overall result would be that I would not be able to format a DD as HD. (Resistors in parallel.) The setup I chose is *real* simple. I didn't want any software solutions that might require me to use up any of my precious RAM (extra driver or command loaded into CONFIG.SYS). I didn't want to create any more complicated circuitry inside my 3.5 drive, like a 3th "auto-sense" switch (not that it couldn't be done.) Simplicity usually works the best (ask LISP programmers! :-) Occasionally I try to read the wrong size floppy in the wrong switch settings. No big deal. I get the usual dos barf "abort, ignore, retry, etc", flip the switch, and hit 'R'. Works like a charm. Erez. A wank's morning starts one machine | Arpa: ezk@cunixf.cc.columbia.edu clock cycle after midnight. | Usenet: ...!rutgers!columbia!cunixf!ezk -HebrewWank #1 (US meaning, not UK!) | Bitnet: ezk@cunixf, erzus@cuvmb
dlou@dino.ucsd.edu (Dennis Lou) (07/21/90)
In article <25160@nigel.udel.EDU> ih@udel.edu (Charlie Ih) writes: >In article <1990Jul19.193954.29829@cunixf.cc.columbia.edu> ezk@cunixe.cc.columbia.edu (Erez "HWank1" Zadok) writes: >>In article <803@digi.lonestar.org> mfrohman@digi.lonestar.org (Matthew Frohman) writes: >..... >>:-) utilize my 5 years of EE studies and put a switch instead. I opened my >>machine and after a few screws (no jokes please) got to the circuit board of >>my 3.5 drive (I think it is a Mitsubishi) where I found a small switch on >>the front right corner of the board. I soldered out that switch. Put a >>hole in the left front panel of my drive and made sure the location of the >>external switch did not interfere with anything inside. ..... >The information is very helpful to others as well. I hope we can have >more of this kind information to help each other. Congratulations >and thanks. Just curious, why could you just leave the switch there >(in open position) and connect the "external" switch in parallel with it? >This would require less work but more important have less chance to damage >the circuit board. Since I don't know the actual situation, maybe >the removal of the switch was necessary. Thanks again! On my Sony, DD closes the switch while HD opens it. It makes sense because the switch isn't activated on HD since HD has a hole. With DD, the blocked hole touches the switch. I plan on cutting the trace on my switch, then putting a 3 position on it giving me "Forced 1.44M", "Forced 720k", and "Autodetect" modes. You can probably imagine the circuit yourself... -- Dennis Lou Disclaimer: I don't use lame disks. dlou@dino.ucsd.edu "But Yossarian, what if everyone thought that way?" [backbone]!ucsd!dino!dlou "Then I'd be crazy to think any other way!"
rick@wet.UUCP (Rick Rutledge) (07/22/90)
Matthew Frohman writes: >I have a pair of those floppy drives which insists on detecting for me, >if there is a hole in my floppy disk. I would like to install a toggle >switch to enable/disable the detector. Ideally, I would like it to have >3 positions: HD, LD, or auto detect, but I don't know if that is possible. >Simply having 2 position (detect, no detect) would be sufficient. I need >this because I have disks formatted at 720K for my laptop that my PC insists >are HD, since they have a hole in them, so I cannot write info to that disk >on my PC without scrambling the FAT. If the disks have a hole in them, they were manufactured with high-density media in them (unless you've found a mfr. who is totally ignorant of the standard). It would be in your best interest to use disks at the `density` for which they were manufactured, but that's up to you. It sounds more like an OS problem than a drive problem, really. The system should really check for that hole when formatting the disk - a preformatted disk should force the OS to check the *disk* for the format; the holes don't tell you, for instance, whether the disk is formatted on both sides or not. For the simplest solution, look to your old 5.25" floppy disks. Cover the hole in the disk with a floppy disk write-protect tab. (The thin plastic tabs are better than the foil or paper ones. >BTW. I have a HD 5 1/4 and a HD 3 1/2, but I really want this for the >3 1/2, though I would thing it would be the same process for both. I'm not sure I understand how this would apply at all for the 5.25" drive... -- ------------------------------------------------------------------------------ Rick Rutledge {hoptoad|ucsfcca|claris}!wet!rick rick@wet.UUCP "Voici le secret." dit le renard. "On ne voit bien qu'avec le coeur. L'essentiel est invisible aux yeux." -Antoine de St. Exupery, _le Petit Prince_
nelson@sun.soe.clarkson.edu (Russ Nelson) (07/22/90)
In article <803@digi.lonestar.org> mfrohman@digi.lonestar.org (Matthew Frohman) writes:
I have a pair of those floppy drives which insists on detecting for
me, if there is a hole in my floppy disk. I would like to install
a toggle switch to enable/disable the detector. I need this
because I have disks formatted at 720K for my laptop that my PC
insists are HD, since they have a hole in them, so I cannot write
info to that disk on my PC without scrambling the FAT.
Wrong solution. Better to make the hole match the contents of the disk,
or vice versa. If it's got a hole, and it's formatted as 720K, cover the
hole. If it's formatted as 1.4M, and it doesn't have a hole, make one
with a disk punch. That way, the disks you create will also be usable
on other machines that do autodetect.
--
--russ (nelson@clutx [.bitnet | .clarkson.edu]) Russ.Nelson@$315.268.6667
In Communism's central planning, citizens are told "you will make widgets".
In Capitalism's advertising, citizens are told "you will buy widgets".joonsong@monsoon.Berkeley.EDU (Suk-Hyun Song) (07/22/90)
The source of the problem that make 3.5" disks unreadable is the disk controller. Most HD/FD controllers insist on using the hole detector on the 3.5" disk drives to determine whether the disk is high density or double density. The most notable among these is the Western Digital controllers. This can be considered a feature or an annoyance depending on your point of view. The solution to this problem is replacing the controller. I have such a controller. It is an MFM 2:1, 2HD, 2FD controller. I used it for about 6 months with no problems reading, writing, and formatting 720K and 1.44M disks irregardless of the hole. Depending on how the disk was formatted, (format a: /t:80 /n:9 || format a: /t:80 /n:18) any disk could be 720K or 1.44M. I later replaced the MFM controller with an RLL 1:1 controller which no longer lets me do this. (I lost the ability to use 720K as 1.44M disks but I got faster transfer rate and more capacity.) If anyone out there is interested in the MFM controller, I would be happy to sell it to you. Make me an offer. Reply to joonsong@ocf.berkeley.edu.
ttak@uhura.cc.rochester.edu (Timothy Takahashi) (07/23/90)
In article <1990Jul22.015706.16479@agate.berkeley.edu> joonsong@monsoon.Berkeley.EDU (Joon Song) writes: > >The source of the problem that make 3.5" disks unreadable is the disk >controller. Most HD/FD controllers insist on using the hole detector on >the 3.5" disk drives to determine whether the disk is high density or >double density. The most notable among these is the Western Digital >controllers. This can be considered a feature or an annoyance depending >on your point of view. What about using the disk formatter that is part of PC-TOOLS. It allows me to format 160k,180k,320k,360k and 1.2mb 5-1/4 disks. Perhaps it will let you format 720k 3-1/2" disks in a 1.44mb drive. tim
chaz@chinet.chi.il.us (Charlie Kestner) (07/23/90)
In article <1361@wet.UUCP> rick@wet.UUCP (Rick Rutledge) writes: >Matthew Frohman writes: [stuff deleted] > > >If the disks have a hole in them, they were manufactured with high-density >media in them (unless you've found a mfr. who is totally ignorant of the >standard). It would be in your best interest to use disks at the `density` >for which they were manufactured, but that's up to you. > >Rick Rutledge {hoptoad|ucsfcca|claris}!wet!rick rick@wet.UUCP This was hashed out on Compuserve over a year ago. Unlike the 5.25" disks, the low-density and high-density 3.5" disks are VERY close to each other in terms of recording sensitivity. (Low-density=600 oersteds, High-density=630 oersteds.) The person who had put this up (I no longer have the message avail- able) had called various floppy manufacturers, and asked their engineers "If the sensitivities are SO close, can't you simply format the low- density as high-density?" "Welllllllll...we really can't SAY that." It's pretty much a given that 3.5 l-d disks will function perfectly as h-d disks (although there is always that "little voice in the back of your mind"...). In any event, since one can get 3.5" HD from places like MEI Micro for $ 0.89, I don't know why anyone'd bother with that hole-punching business anymore. (And if you DON'T punch, it gets kinda tricky to try to give someone else a disk.)
gettys@regent.enet.dec.com (Bob Gettys N1BRM) (07/23/90)
In article <803@digi.lonestar.org>, mfrohman@digi.lonestar.org (Matthew Frohman) writes... > I need >this because I have disks formatted at 720K for my laptop that my PC insists >are HD, since they have a hole in them, so I cannot write info to that disk >on my PC without scrambling the FAT. > > > Thanks in advance, > Matthew A much simpler solution is to use a piece of opaque tape to cover the hole. Works just fine! It also doesn't "disfigure" your computer/drive in view of eventual resale value. /s/ Bob
jeffj@synsys.UUCP (Jeff Jonas) (07/24/90)
I like the hardware solutions, but these are less intrusive
and require less skill and tools.
I have 2 ways to trick my drive to writing disks with the
write protect hole
(the same trick can be used for low/high density).
1) put a piece of tape or "post-it" on the BOTTOM of the hole.
This will (de)press the switch when the floppy is inserted.
Be sure not to interfere with the hub!
2) I opened the floppy drive and taped down the switch.
This is less dangerous to the drive than desoldering/jumpering.
I'm not going to mess with boards with surface mounted parts,
especially when it's my money!
All the 3.5" floppy drive mechanisms I've seen require the disk to
move down to engage, so the hole detectors are tiny button switches,
not the optocouple used for 5.25" drives.
This is similar to the write protect holes used in cartridge tapes,
audio cassettes, and videotapes.
They're sensed by a pin/lever to a switch.
This means that the hole needs to be covered, but not light proof.
Ordinary cellophane ("Scotch") tape will suffice, but that tends to
leave the envelope sticky.
By the way, the 3.5" floppy drives used in the PS/2 don't have
a switch to detect density. The mechanism is half height, but
in a full height casing to fill the full height cabinet bay.
Jeffrey Jonas
jeffj@synsys.uucpdel@fnx.UUCP (Dag Erik Lindberg) (07/26/90)
In article <1184@gold.GVG.TEK.COM> grege@gold.GVG.TEK.COM (Greg Ebert) writes: > >The difference between 720K and 1.44M formatted diskettes is single vs. double >density, and not narrower tracks as in 1.2M floppy drives. All 5.25" drives >are asumed to be double density. > Bzzzzzt. Wrongo. No existing standard floppy controller for the PC family (after-market-special-whizzbang-read-everything-in-the-world controllers excepted) can read or write single density. It is true that recording frequency and encoding method change between 720k and 1.44M, but 720k is definitely *not* "single density". It is in fact the exact same format used on 360k DSDD (that's "Double-Sided-Double-Density". Ever wonder why you see that on standard 3.5" disks?), which is why even the original IBM PC can be coaxed into reading/writing 3.5" disks. >My MSDOS technical information regarding FATs, etc is a bit outdated, but it >does describe single and double-density 8" diskette support. Basically, an >attempt is made to read the disk in single density. If a read-error occurs, >an attempt will be made using double density. I conclude that it is a BIOS >constraint whether your 3.5" drive is 720K or 1.44M. Any BIOS gurus out there >wish to comment ? There is indeed a BIOS constraint. But also a hardware constraint. Mainly, if your machine has a FD controller that can handle 1.2Meg 5.25" disks, then you can handle 1.44M 3.5" disks, since the recording format is essentially the same! Yes, of course there are some minor differences, stress *minor*. -- del AKA Erik Lindberg uunet!pilchuck!fnx!del Who is John Galt?
jim@world.std.com (James D. McNamara) (07/28/90)
In article <598@fnx.UUCP> del@fnx.UUCP (Dag Erik Lindberg) writes: >There is indeed a BIOS constraint. But also a hardware constraint. Mainly, >if your machine has a FD controller that can handle 1.2Meg 5.25" disks, then >you can handle 1.44M 3.5" disks, since the recording format is essentially >the same! Yes, of course there are some minor differences, stress *minor*. >del AKA Erik Lindberg uunet!pilchuck!fnx!del BIOS constraint, indeed. I plugged a 3.5" drive into a Zenith, at work. Had the vanilla controller, but the DOS 3.2 ROM chips (yeah, drag) only knew about 360K and 1.2M formats. No prob! Formatted and did r/w to a 3.5" with 1.2M capacity -- how's that for something completely different? Well, a few P.O.'s later the DOS 3.3 ROM chips were in, and life returned to 1.44M-normal. -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - James D. McNamara, jacked-in at... | jim@world.std.com 45 Cleveland Street #1, Arlington, MA 02174-6915| Phone: (617) 648-2440
ih@udel.edu (Charlie Ih) (07/29/90)
In article <1990Jul21.083532.15802@cunixf.cc.columbia.edu> ezk@cunixf.cc.columbia.edu (Erez "HWank1" Zadok) writes: >In article <25160@nigel.udel.EDU> ih@udel.edu (Charlie Ih) writes: >> In article <1990Jul19.193954.29829@cunixf.cc.columbia.edu> ezk@cunixe.cc.columbia.edu (Erez "HWank1" Zadok) writes: >> >In article <803@digi.lonestar.org> mfrohman@digi.lonestar.org (Matthew Frohman) writes: >[...] > >I gather from your question that you're not familiar with basic electronics. >That's ok. Here's an explanation I hope would make sense. > >I could not have left the internal switch in open position b/c the minute I >put a DD floppy inside (no 2nd hole) the internal switch would be pushed >down, thus creating a short between the two points. ..... Thanks for the explanations. If you had indicated that the switch was activated by the disc, then it was necessary to removed it as you have done correctly. I thought that's what I phrased in my question. I guess I did not make it clear. I used the phrase "less chance to damage it" only in a relative sense. An article following yours describes the Sony drive. Thanks for the information. Charles S. Ih, Prof. of Electrical Eng., research interests in electronics and opto-electronics.