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Hello everyone!
I have an old 8-bit floppy card I run my 3.5" 1.44 MB floppy drive in my XT with. The problem I am experiencing is when the machine is powered on, it searches the floppy upon BIOS conclusion, then attempts to read the disk, fails, and boots from the C:. Upon loading DOS, when I type A: and hit Enter, the disk spins and the light on the drive comes on, but then it prints an error on the screen saying the General Failure Reading A: RETRY? FAIL? Hitting Retry results in the same read error failure, and when I hit Fail, it throws the error of Drive No Longer Valid.
Heres the catch: I swap the motherboard out for a 80486 33 MHz and the card and floppy work flawlessly! I can boot from a floppy or read from one once booted into DOS. I have 3 486 boards and 3 8088 boards. The card and floppy work in the 486's and fail in ALL of the 8088's. They originally came in a 8088 computer, and I remember using them and they worked flawlessly.
Is there a special jumper setting to make the card and drive work in the 8088's again? Do the 8088's have to be working in 8 or 10 MHz Turbo mode to be able to read and use the floppy?
Thank you for all your help!
Emer
There's usually jumper settings for more than one floppy address on those. Try a different address. If the card has no documentation you may be able to find info here:
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8088 and previous computers cannot support a 3 1/2" 1.44mb floppy drive, or a 5 1/4" 1.2mb, but they can often support a 3 1/2" 720kb one, and of course they support a 5 1/4" 360kb one.
Support for 3 1/2" 1.44mb, or a 5 1/4" 1.2mb is built into 286s and up."I remember using them and they worked flawlessly."
If they were 3 1/2", they were 720kb.
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There were floppy cards that gave 1.2 and 1.44 support for 8088 machines. They had their own bios to get around the lack of built-in support. Back in the day I had several dozen I got at auction and was able to put together some really nice (for the times) XT machines. I probaby still have a few around here somewhere.
But that got me to thinking, if someone had removed the bios chip, disabled it or it was bad the card might still work in 286's and above as a regular card but not in 8088's.
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Thank you guys for your input! DAVEINCAPS, I never thought that the BIOS chip might be disabled. I have 2 individual floppy cards it turns out... however only 1 works in the 486. Neither work in the 8088 and I just realized yesterday that after attempting to read a floppy disk in the 8088, the data is scrambled on that disk when I try to read it in my primary machine (Dell Precision 690) or any other computer with a floppy disk. Any idea what might cause this?
Emer
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"I never thought that the BIOS chip might be disabled. "
The vast majority of the cards out there with floppy controllers on them cannot support 1.44mg or 1.2 mb floppy drives on 8088's and previous and DO NOT have a bios chip for that pupose on the card. I have personally never encountered a card than can and has the bios chip that DAVEINCAPS has mentioned, in fact I didn't know they existed.
The floppy controller only requires 8 bits.
It's probably a lot easier to find a used 720kb drive. Some bioses have no native support for 720kb drives, but as I recall you can use a debug routine or similar to get one to work in that case.I know you could in the past get 8 bit IDE hard drive controller cards for use on 8088's and previous, but as far as I was able to determine they only work with 8 bit IDE hard drives - both are now very old and rare.
"..the data is scrambled on that disk.."
I assume you mean on the floppy disk you tried to read.
I have only seen that problem sometimes when the data cable was improperly connected when the drive had a floppy disk inserted in it, such as it was one position out on the header (I don't think having the connector backwards will hurt as long as it's on all the pins), and in that case you don't even have to have accessed the floppy yourself - it may not require anything accesses it. In that case there's nothing I know of you can do about the scrambled data, but the floppy is usually fine once it has been re-formatted.
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Yeah, either a loose or bad cable or maybe a slightly misaligned head such that a disk formatted in that drive may work OK in it but not another drive.
I only used those cards in turbo xt's. (Why mess with a piddly 4.77 mhz with you can blow by it with an 8 or 10 mhz?) But in general I don't think it should matter. Some of the early IBM PC motherboards had option rom sockets that may make addressing difficult, but that's just a guess.
The cards I got at auction were I believe Jameco cards but I couldn't find a link to any. I've got all that old stuff boxed up in the garage and might check when I get around to it. I got a few other brands from PCs I stripped down. And now that I think about it, some of those I couldn't get to work right in other PCs.
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Okay, I've been doing my research. The one I KNOW is out of an 8088 is a Kouwell model KW-516E, which is identical pinout wise to the KM-516, which is listed http://www.peteweb.com/ftp/mirrors/... . The card used to have a battery in it, but it is long since been removed... possibly ruining it??? The big black chips in the picture of the KM-516 are +B8836 MM58167AN-T and 8941-CS UM8397 from top to bottom respectively. I dont see any settings for a BIOS or floppy anywhere.
I took my DTK PIM Turbo 8 MHz 8088 board and installed my video card and the KW-516E floppy card in it, setting the disk number to 1 on the dip switch board, and then connected a 360KB 5.25" drive to it and attempted to get it to boot from it. I tried a formatted 360K disk and a 1.2M disk, each with the basic command.com, io.sys... files for a very basic boot. The computer found no boot record and when striking a key like it wanted, the disk spun and the read light was on, but the head wouldnt move. CTRL+ALT+DEL would no longer work after that point either until the machine was hard-reset. When my 30MB Mini-Scribe was added to the config, it would boot from it into DOS 6.22, but then would fail to read the floppy disk.
The other controller turned out to be an Epson one out of a 286 machine, probably the reason it would boot with no problems from a 1.44MB bootdisk on a 486 machine.
I've been watching eBay for an old card that might work in my case, but i really dont know what i should look for... How do i know FOR SURE that it supports 1.44MB disks? Thank you guys!
Emer
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The card you linked to is a 16-bit card, meant to be used in 286's and up. The bios' on those already supports 1.2 and 1.44 so the floppy cards don't have to be configured. Even if that card worked in an 8088, it wouldn't have supported 1.2 or 1.44 drives as that would be a function of the computer's bios.
A card that will work in an 8088 and have support for 1.2 and 1.44 drives will look something like the one here:
http://www.lemmus.eu/th99/c/0-9/217...
That is, when you put the card in one of the slots on your 8088 all the card 'fingers' will be in the slot and there won't be any behind the slot as there is in your link above. Also you'll need to verify it does have 1.2 and 1.44 drive support and isn't just a regular 8-bit card supporting 360's and 720's.
360K and 1.2M drives look the same to you and I but the computer sees them differently. The only way to tell the difference is to check their model numbers. 720K and 1.44 also look the same but the 1.44's will have a sensor just inside the drive door on the right side to detect the hole that 1.44 disks have. That way the drive knows whether you've inserted a 720 or 1.44 disk. 720's don't need a sensor since they won't work with 1.44 disks.. But again, you can also go by the model number. The drive settings on the 8-bit cards must match the drive type. You can't call a 1.2 a 360 or vice versa and have them work.
The 'drive select' (or DS), cable and the drive's position on the cable are something else you need to check. On older 5.25 drives, especially 360's, there were 4 DS possibilities, either D0, D1, D2 and D3 or D1, D2, D3, D4. When using a cable with the 7-wire twist between the two drive connectors you'd want both drives to be at the second selection--either D1 or D2 depending on which way they were numbered. The drive on the end would be A: and the drive on the middle connection would be B:
When using a cable without the 7-wire twist you'd want the A: drive jumpered to the first DS and B: jumpered to the second DS. Position on the cable won't matter in that situation.
Older 3.5 drives used DS setting too although they usually only had two positions so you need to pay attention to that. Most 1.44 drives now are preset to the second DS.
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Ya know, this has really opened my eyes! I must admit I have been very spoiled over the years of working with a floppy drive and machines new enough you just throw one on a cable and go! But okay, heres today's findings:
I uploaded pictures of the hardware and tried to get a snapshot of the old 8088 herself, but the picture looks very busy... I'm not much of a photographer. http://usera.imagecave.com/Redline7...
In these links, change the last number before .JPG from 0-8 to see all the pictures.
DAVEINCAPS, the first picture is of the card I'm trying to use. Good catch to see the link I sent you was a 16-bit card, and i apologize for that! I didnt even notice myself! This card I assure you is indeed an 8-bit card, but support for it is few, far inbetween, and frustrating over a 28K dial up connection.
The 3.5" on the desk is a Toshiba ND-352TH-A, which I believe is a 720K, which is good. The 5.25" on the desk is a TEAC FD-55GFR, a 1.2M drive - so that one probably isnt supported by the card.
The 5.25" in the computer is an Epson SD-600, another 1.2M drive - strike 2 for me.
And the 3.5" in the computer I know is a 1.44M since i believe I robbed it from a Pentium I server.
So... This means I need to find a card that supports 1.44 and 1.2M or start hunting for a couple OLD drives and disks. I dont believe you can format a 1.44M as a 720K, can you? I am going to try that old Toshiba floppy and see if I have any old 720K's lying around somewhere.
DAVEINCAPS, I'm not sure I understand about the DS settings... The cable in the computer has a new floppy style connector that plugs into the card, and 2 old style connectors at the end, and there is a wire twist inbetween them. Assuming I want the A: to be the 3.5" drive, how should I configure those? Thanks again!Emer
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One more question: On the 3.5" drives, on the back where it plugs in there is a jumper and the ability to set it to either A or B. I'm sure you can see that in the pictures I linked to. Which setting do I use? What are the differences in the settings?
Emer
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You probably don't have to touch the A /B jumper(s) at all. Just use a data cable that has three connectors and have the drive on the connector on the end after the flipped wires and it will be seen as A.
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So the 8-bit card you think works with the 1.2 and 1.44 drives is the one in the picture and it's a KW-516E? I couldn't find any info on it but it doesn't look like the typical 8-bit FDC card with high density drive support. I'm thinking that maybe neither of those cards you have will have high density drive support. I'll check in the garage in the next few days and see if I can find any.
I also couldn't find any info on jumper settings for that 720 so as T&W says just attach it to the end connector and see how that works out.
I got my first 1.44 drive at the flea market. When I first tried it with the high density drive card in the turbo XT I was building it didn't work. I finally had to take it to a shop and they looked up the correct jumper settings. Later on I would pick up a few in external drives from auction. They were old OEM drives from Teac. They wouldn't work either as internal drives until the jumpers were changed. So with old drives like that you may need to change the jumper setting unless you're sure they were previously used in the same way you plan on using them.
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"I'm thinking that maybe neither of those cards you have will have high density drive support. "
If you use the 720kb drive with the card it should work for sure. I don't see a bios chip on that(those?) card(s?). The cards DAVEINCAPS are very rare and you're very inlikely to come across them - I never have. You may have to disable the onboard MFM or RLL controller if the card has that (they also have a 34 pin header, same as for a floppy drive).
Note that if you have old data cables for MFM or RLL drives, if the cable has three connectors the wires are flipped between two connectors but the ones that are flipped are different from those fo a floppy cable with 3 connectors - the headers for both are 34 pin, and their wiring is very different.
You can format a 720kb disk in a 1.44mb drive, or a 1.44mb disk in a 1.44mb drive as 720kb if you place tape over one of the two square holes in the floppy. The 1.44 drive knows whether you have a 720kb (1 hole) or 1.44mb disk (two holes) by means of two microswitches that sense whether the one hole is there or not.
I've never tried a 1.44 disk in a 720kb drive that I can remember, but in theory you should be able to have it recognized as 720kb if you format it to 720kb.
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Okay, we're getting somewhere here :)
I would have to agree with both of you that the card (support sucks for it huh?) I have doesnt support high density drives. So all of them but that old 720K Toshiba drive will not work in this system, unless it is a jumper thing like you said, DAVEINCAPS. I'll definately have to look into that.
However I did plug that Toshiba drive in, setting the jumper to A and placing it at the end of the twist. I tried the tape trick with a 1.44MB floppy in my USB floppy drive on my Precision, and it threw a fit! (Stupid Vista...) So I rebooted the thing into XP, and it also threw a fit (Stupid XP...) SO I booted up my good ol' 486 and sure enough, it would format it with no arguments. I then had a 1.44 formatted as 720K. For tests I used the files command.com and a midi file I had on the 486. Of course since it is not a boot disk the XT wouldnt boot from it, but after it found its way into DOS 6.22 I WAS able to access the floppy drive and I WAS able to read the disk!!! :D :D :D
I noticed a lot of small utilities (Memtest32 for example) refuse to install on the custom floppy because it cant figure out sectors and all that great jazz... I also found a utility online by 2M that is supposed to act as a software BIOS extension that when loaded into memory (about 4K) will add high density disk support to any machine (XT's too) with floppy drives. Also it allows some funky compression attribute so you can write "more" onto a disk than its rated capacity. Skeptical as I am, I thought it might be worth a shot.
The other drives I will see if the program will allow them to work after the machine has been booted and the program loaded. Of course the XT will never boot from a 1.44 MB floppy, but thats okay... so far :)
I'll follow up on how this works. Thanks again all!
Emer
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Apparently you can only format 1.44 disks from XP:
http://support.microsoft.com/defaul...
Other sizes must be done from the command prompt. That's probably at least part of why you couldn't format a 720.
You can use either 1.44 or 720 disks in a 720 drive. (Of course you'll have to format a 1.44 as 720 before using it.) You don't need to cover the sensor hole since 720 drives don't have the sensor and therefore can't tell the difference. But if you then use that disk in a 1.44 drive you must cover the hole. (Both 720 and 1.44 drives have sensors on the left side just inside the door to detect if the 'read only' hole is covered. But only the 1.44 has a sensor on the right to detect the disk density.)
When formatting a 1.44 disk as a 720 in a 1.44 drive you need to cover the hole first and then use the format/f:720 command.
I'll try to check on the FDC cards tomorrow.
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