Floppy drive diagnostics help

[kamiboy]

Before I take a sledge hammer to this stylish paperweight of a Compact IV I have here I thought I'd give its floppy problems a final looking at. At the very least it will increase the resale value if I get one of them going again.

What puzzles and intrigues me the most is the error message below:

Human.sys が壊れています (...)

This message shows up when I insert a 1.25MB formatted floppy with a valid X68000 image on it. If I insert an invalid floppy, I get a different message saying something to the order of, cannot read from disk.

This obviously means that the floppy drive is capable of reading the disk enough to recognize that there is valid floppy disk in there. So it is serviceable enough to pass the initial boot step but some other subsequent step halts the boot process.

Is anyone privy to the boot procedure of these machines?

What exactly does the above message mean? What is the significance of Human.sys being broken? I think knowing that could give some insight into what needs repair.

In other news I tried to wire a floppy cable to the daughter-board in hope of using a generic 3-mode PC floppy drive to get the machine to boot anything.

As expected it didn't work. According to my multimeter probing I confirmed that my wiring is correct, but when I turn on the machine with a floppy in the drive all I get is the access LED turning on momentarily, but no attempts to read the disk is made.

If fact when I insert and eject a floppy nothing happens, the machine does not react. I tried two different kinds of floppy drives. One native 3-mode, and another that required a bit of modification to act like one.

I followed this diagram to connect the two:

http://gamesx.com/wiki/doku.php?id=x68000:pc_floppy_drive

[lydux]

This message : "Human.sys が壊れています" comes from the second stage bootloader located on the very first sectors of the HumanOS floppy disk.
This bootloader is 3KBytes long.

Exactly, the bios does load it first into main RAM (at address 0x2000 if I remember correctly), then execute it.

This small piece of program code should try to locate a filename within the disk FAT called "HUMAN.SYS" (the Human68K kernel). Once found, load its content entirelly at address 0x6800 (main RAM), then check for the XFile magic flags (the 2 first bytes of an Human68K executable : "HU" = 0x4855). Expect then to start the kernel.

If the XFile magic flag ("HU") does not match, your message "Human.sys が壊れています" will pop !

Sorry, it's a bit technical but you can conclude that your floppy drive can load correctly the small second stage bootloader, look into the FAT, but something goes wrong after that : it's unable to load a bigger file (the kernel) or does load wrong datas.

I would say : a bad floppy disk formatting, or a misaligned floppy drive heads.

[kamiboy]

I know programming so that is not too technical at all.

I was thinking something in the same line. That the Floppy drive first determines whether the disk format is appropriate or not, then tries to look at a specific sector for some sort of boot loader which then takes things from there.

I thought corrupted Human.sys was due to the bootloader not being found in the sector expected, but is seems that the machine can find it and loads it either entirely or partially.

The Compact floppy head should in theory be fairly easy to align. Only the top head is able to move, and it is held down by an easy to access screw. You can even move it while the disk is inserted and spinning if you are brave enough.

Thing is no matter where I move the damn thing it wont boot from the disks.

Floppy drive 0 used to be able to read some disks fine mind you. Then after some fiddling around it just stopped. This happened right around the time that floppy drive 1 stopped functioning altogether, completely dead.

Also I just found out that my efforts of connecting a PC floppy to my Compact were futile because X68000's cannot boot from PC floppy drives without drivers installed in the S-RAM. Catch-22.

Next, trying to connect my sole semi functioning X68000 floppy drive to a PC in order to try and align the head, or something.

On a slightly other note. How do you format a 1.25 mb disk in pure old school DOS? In BIOS I am supposed to turn on 3-mode but leave the drive type as 1.44, correct?

The commands used by the XP format command does not work in old time DOS. It seems the old school DOS format command was less flexible.

[caius]

Hi, the diagram to connect external FDD connector to a standard PC FDD is wrong because it lacks of /Disk Type Select* signal.Besides the READY signal on X68000 is PIN 17 and not the 18.
So, assuming you want to connect external FDD connector of your CompactXVI, you need a special 40 pin D-sub micro connector like this:


http://it.mouser.com/Search/ProductDetail.aspx?R=10140-3000PEvirtualkey51750000virtualkey517-10140-3000PE

Otherwise you can take the signals directly from the daughterboard as you have done, so take a multimeter and find the exact correspondance between the pinout  of CompactXVI FDD external connector (which is identical to the one of  DB-37 connector of the Twin Tower models plus some extra GROUND signals on pin 38-39-40)  :

http://gamesx.com/wiki/doku.php?id=x68000:floppy_pinout

and pads of internal daughterboard.


So, attached is  the correct diagram to connect external CompactXVI FDD connector to generic PC FDD tested and working with two Samsung SFD-321 FDD (this model seems to works very well but you have to jumpers some pads on its PCB in order to activate 3-mode 1.2MB) :



Take in mind that the generic FDD will miss the xtra-funsction (LED blink, soft-eject) and you will need the EXPFD.X driver to porperly make them recognized under Human OS .Besides, if you want to boot from these FDD you will need the SRAM version od EXPFD.X driver (called S_EXPFD.R).Attached are both  drivers in a single zip.

P.S.

To format a 1.25MB under DOS you have first use a 1.2MB FDD, I recommend you a USB one like this I have:

http://it.bestshopping.com/prezzi/Sony-PCGA-UFD5-SONY-VAIO-FLOPPY-DISK-DRIVE-ESTERNO-SONY-usb.sku=PCGA-UFD5%7C.html


Then, The correct syntax for formatting is:

FORMAT X: /A:1024 /T:77 /N:8 /U

where 'X' is the drive letter assignement

Tested and working under DOS prompt of Windows XP 

[caius]

Kamiboy, I updated the diagram (removing two not needed signal, DS0 and DS1) so, please, download it again !:)
And remember that when you use external FDDs the  switch on your CompactXVI has to be on position 0-1 (so internal FFD are devices '0' and '1' and external ones are '2 and '3')!

[kamiboy]

Thanks Caius, but the only reason why I wanted to attach an external PC floppy to my Compact was to use it to boot into Human68K so as to try and see whether SWITCH.X was able to detect the, presumed dead, Power Monster II SCSI CF card before I sent it back to its maker.

If I cannot boot from a PC floppy drive without putting stuff in SRAM first then it is useless. I'll remove the cable from the daughter board. If I ever get so far along as to be able to boot anything from my Compact then I no longer need an external floppy drive.

I actually already have an external USB floppy drive, and I've successfully written 1.25MB X68000 floppies with it. Ones that my Compact could boot from before one of its floppy drives gave up the ghost and the other one went on permenant strike.

What I wanted to know is whether it is possible to write such disks from pure old school DOS. Not XP command prompt or the versions of DOS that Win 95 and up boot from, no sir, just plain old DOS and a plain old PC 3-mode floppy drive on a plain old DOS PC.

Reason being, I wanted to source X68000 floppies from other hardware configurations just in case my Compact floppy drive would like those better for some reason. It is a long shot I know, but long shots are all I have left at this point.

That format command you sent for XP does not work in pure DOS.

I guess I could find a copy of Win95 and install it on my DOS machine. Only if I remember right installing Win95 is a lengthy ordeal. Don't want to be arsed unless there be no choice.

[kamiboy]

Actually the Mini Centronics 37 pin External floppy port on the Compact can easily be found on ebay. Turns out some printers used cables with a Mini Centronics 37 on one side and DB25 on the other. If you just search for mini centronics on ebay you'll find a tonne of them.

Also you might want to edit this link as well: http://gamesx.com/wiki/doku.php?id=x68000:pc_floppy_drive

That is the one I actually used to do my wiring. You say that Ready is actually 17, not 18? That is a big typo.

And Disk Type Select should not matter since, if I understood you right, it is not present on PC floppy drives anyway, right?

[kamiboy]

Come to think of it, anyone privy to the pinout on the X68000 internal floppy drives?

Should be a piece of cake to attach it to a PC using a cut up PC floppy ribbon cable by soldering each wire to the right solder pad on the compact floppy top mother board. But not knowing the pinout makes that impossible.

[caius]

Come to think of it, anyone privy to the pinout on the X68000 internal floppy drives?

Should be a piece of cake to attach it to a PC using a cut up PC floppy ribbon cable by soldering each wire to the right solder pad on the compact floppy top mother board. But not knowing the pinout makes that impossible.

Attached below (X68000 Compact internal FDD pinout.jpg) is   the pinout of the CompactXVI internal FDD (keep attention, there is also +5V).So,  on the basis of this pinout, this would be the wiring:


X68000 CompactXVI             Signal                        PC (Shugart)
Internal floppy connector
(Shugart)
                                     
17                                     Disk type select             2
8                               DS3                                  6
31                               Index                                  8
5                               DS0                                10
6                               DS1                                12
7                               DS2                                14
12                                Motor ON                          16
14                               Direction                        18
15                              Step                                20
10                              Write Data                        22
13                              Write Gate                        24
29                              Track 00                        26
30                              Write Protect                        28
33                              Read Data                        30
16                              Side Select                        32
28                              Ready                                34
1-9-11-32-34              Ground                                1-3-5-7-9-11-13-15-17-19-21-23-25-27-29-31-33






Regarding the diagram for connecting generic PC FDD to X68000, follow the one I posted.READY signal is 17 and not 18.Personally I connected also PIN 1 of X68000 (/Disk Type Select) to PIN 2 (Density Select) of the PC FDD, whit this configuration everything works fine.
Remember to use a 1.2MB FDD like the Samsung SFD-321 (with proper jumper settings)

Regarding CompactXVI external FDD connector, it's a 40 pin D-sub micro connector but, as you said, you can use a 36 (I think not 37) pin Mini Cetronics, last GROUND PINs (38-39-40) will not be used.

[kamiboy]

Thanks a bunch caius, I'll try wiring up this compact floppy right now. As for the +5V locations, they are pin 2 and 3 I assume?

And pin 1 would be the left most one looking at the back port of the floppy drive, am correct?

It certainly seems like that judging from the pin numbering of the floppy ports on the X68000 motherboard and by following the traces for pin 2 and 3 on the floppy top board. Just making sure.

[caius]

Thanks a bunch caius, I'll try wiring up this compact floppy right now. As for the +5V locations, they are pin 2 and 3 I assume?

Yes, PIN 2 and 3 are +5V.

And pin 1 would be the left most one looking at the back port of the floppy drive, am correct?]And pin 1 would be the left most one looking at the back port of the floppy drive, am correct?

Correct.If you look at FDD PCB there are silkscreenings '33-34' on the right and '1' on the left of the header.So, this time, you can't go wrong

[kamiboy]

Well gents, you all get three guesses as to exactly how much success I had in this latest venture, and the first two do not count.

As I write this I am resisting the violent urge to put on the old wooden clogs and do an extended tap dancing number on the bare carcass of my Compact. I assure you it is tempting since doing that would prvide me with the most pleasure I have ever got out of this investment.

Anywaste, vitrol aside, here is how it is.

I connect the Compact floppy drive to my PC and it boots fine without throwing up floppy device errors. So far so good. The head even does klink, clank, klunk sound all PC floppy drives do during boot. Alas once in DOS whenever I try to access the drive I get drive not ready errors.

Funny thing is that the disk never spins whenever the PC is turned on. I am powering the floppy via an external power adapter by attaching a single 5v line to floppy pin 2, and a ground wire to one of the floppy ground pins. If I power the floppy drive without turning on the PC and insert a disk it will start spinning. But as soon as I turn on the PC it stops spinning and the LED turns a solid green instead of red and stays that way until I eject the disk.

I didnt bother connecting two +5V sources to pin 2 and 3 since they are connected anyway I think just one +5V should suffice. I cannot imagine that is the problem.

The compact floppy is supposed to just work when connected to a PC right? No special jumper settings or specific options in the PC bios, correct?

The floppy cable is not supposed to have that crazy loop in it either, correct? Just straight pin to pin to the motherboard, no?

To try and find the correct pins on the floppy cable during soldering I attached the end that was supposed to go into a motherboard to a PC floppy drive and used its solder pads to confirm which pin was which.

I am too tired and my spacial reasoning is too feeble to figure out whether that might cause problems or not, what the motherboard pinout being mirrored or not. God I hope not, I dont want to redo this wiring job.

In fact I am too tired for anything right now. The clogs will have o wait till tomorrow.

[BlueBMW]

Whatever you do, please dont destroy the compact physically.  I know it would give you huge pleasure to do so but please refrain!    If you end up without success it will still be possible to recover some of your investment.   Also, shoot me a pm as I have an idea that may help you.

Byron

[kamiboy]

Worry not, my violent fancies are therapeutic only. I never act on such base impulses.

I just want this silicone sculpture to work so I can start playing some games at last. 10 minutes of Bubble Bobble is all I've gotten out of this after over $1000 spent since Febuary.

I also would love for that demmed Core Grafx II I've been trying to fix for over a year to stop being so temperamental so I can put that pointless time sink project behind me as well, but that is another story.

There are other loose end project too. Man, I have been In a depressing rut lately with this kind of stuff.

[BlueBMW]

Believe me I can fully understand the frustrations this stuff can cause....  whatever you do dont try and repair a dead Laswractive Sega PAC.  Those are nothing but frustration!!

What issues are you having with the core grafx 2?

[caius]

I forgot to say you that, in order to connect every X68000 FDD to a PC, you  have to invert two pins (READY and DISKCHANGE/DISK TYPE SELECT) on cable  , read this thread from here:

http://nfggames.com/forum2/index.php?topic=2364.msg33240#msg33240

Probably this was the reason why it didn't work for you.

So, to recap, this is the correct diagram.


17                                     Disk type select             34 (Ready)
8                               DS3                                  6
31                               Index                                  8
5                               DS0                                10
6                               DS1                                12
7                               DS2                                14
12                                Motor ON                          16
14                               Direction                        18
15                              Step                                20
10                              Write Data                        22
13                              Write Gate                        24
29                              Track 00                        26
30                              Write Protect                        28
33                              Read Data                        30
16                              Side Select                        32
28                              Ready                                2 (Disk tpe select)
1-9-11-32-34              Ground                                1-3-5-7-9-11-13-15-17-19-21-23-25-27-29-31-33

Remember to jumper the Floppy to DS1, set the PC BIOS to Drive B and insert a floppy before powering ON the pc.

[kamiboy]

Thanks caius, I guess I need to move those two wires around and hope for the best. From the way the Compact floppy drive was acting it seemed to me that I was very close.

Let us hope this does the trick so I can start looking at doing some head alignment via good old DOS.

Believe me I can fully understand the frustrations this stuff can cause....  whatever you do dont try and repair a dead Laswractive Sega PAC.  Those are nothing but frustration!!

What issues are you having with the core grafx 2?

Ah, the Core Grafx II.

When I first bought it, off of Yahoo auctions, it arrived at my door completely dead. So I did  the usual, exchange all the caps, which did nothing and I got worried.

Long story short, it turned out the fuse was blown. I replaced it and what do you know it was working.

Alas I discovered that after a few hours of play it tended to freeze randomly.

I tried and tried to figure out the source of that freeze. Reflowed every blob of solder on the damn PCB. In the end I ended ripping out the ribbon cable connecting the cart slot to the motherboard and replacing it with custom wiring.

It still freezes though. The funny thing is, as a test, I left it on all night the other day. After almost 24 hours no freezes. I still need to test this out, but I suspect it will still crash during normal gameplay.

There is one last thing I want to try, redo my subpar wiring job in order to remove the excess wire putting pressure on the top and bottom boards. That night I left it on the PC Engine was opened up, so I suspect pressure is the culprit. We'll see.

[kamiboy]

A little update gents. I had a few minutes to spare so I swapped the two wires, changed junper to floppy 1 and set the drive up as "B:" and.... still no dice.

[caius]

A little update gents. I had a few minutes to spare so I swapped the two wires, changed jumper to floppy 1 and set the drive up as "B:" and.... still no dice.

Tomorrow I want to try myself and report here my results.
Have you used a straight cable or twisted one?What is the behaviour of the drive?It spins?

[kamiboy]

Straight cable, no spinning.

When I get home I need to try and wrap my head around whether the pinout I did could be mirrored or not.

[caius]

Found this little floppy DOS utility called Floppy Disk Reanimator.

[kamiboy]

Thanks caius, but I had already found that utility in another thread here on the forums.

Be sure to report on your success with connecting a compact drive to a PC.

I just got finished reconfirming that my wiring job is correct and the pinout is not mirrored.

As I mentioned earlier the disk does not spin when I turn on the PC. When trying to access the drive I either get drive not ready error or some other error depending on how I configure the drive select jumper on the compact floppy and how I change the PC BIOS.

The floppy drive never makes an attempt to spin the disk when I try to access the selected drive no matter what configuration I use.

It is funny, since changing the two wires around when I try to format the drive the format command thinks the inserted disk is 360k.

[kamiboy]

Good news everyone. Looks like that last wire swapping actually had done the trick. Problem was that the floppy head was so out of alignment that DOS would throw up general device error when trying to access the drive. I found this out when deciding to try and run that that Floppy Disk Animator anyway.

God bless the russian that wrote the program, it actually tries to read the whole disk instead of giving up when sector 0 is not found.

Anywaste, I have some aligning to do. 

[caius]

OK, good to hear.For the FLoppy Disk Reanimator instructions you can read here:

http://nfggames.com/forum2/index.php?topic=4984.msg32692#msg32692

So, can you confirm this pinout is good?

CompactXVI internal FDD                                          PC 17                                     Disk type select             34 (Ready) 8                               DS3                                  6 31                               Index                                  8 5                               DS0                                10 6                               DS1                                12 7                               DS2                                14 12                                Motor ON                          16 14                               Direction                        18 15                              Step                                20 10                              Write Data                        22 13                              Write Gate                        24 29                              Track 00                        26 30                              Write Protect                        28 33                              Read Data                        30 16                              Side Select                        32 28                              Ready                                2 (Disk type select) 1-9-11-32-34              Ground                                1-3-5-7-9-11-13-15-17-19-21-23-25-27-29-31-33

[kamiboy]

I can confirm that the above pinout is good as with it FDR works its magic on the drive.

I spent an hour or two trying to align my head. The best I could do was have FDR read every sector on the disk except for the top left row.

No matter where I move the head the top left row always comes up bad. I am guessing that portion is sector 0, which then would explain why the floppy drive refused to boot anything in my compact.

When I go home today I'll struggle with it some more.

If all else fails I can always try to swap heads with the dead drive.

[caius]

So, which is setup for the FDR program?Is there the need of a previous 1.2MB formatted disk?

P.S.
I want to try this program with my four CompacXVI FDD but first I ahae to change that secret capacitor since I was not yet able to separe the two assemblies

[kamiboy]

FDR analyzes the disk surface and automatically determines what format it is formatted as. I believe that I've used both a 1.44 and 1.2 formatted disk on it with no problem.

Bear in mind that if your head alignment is way off the program could make a wrong assumption as to the format. At the very least I experienced that if the head was way off FDR would show less cluster present in its graphical representation.

[caius]

OK but you used a  1.44 MB formatted disk? I know X68000 FDD cannot R/W 1.44 unless you use some software driver.

[kamiboy]

You mean that Compact floppy drives are incapable of reading 1.44mb formatted disks out of the box even when connected to a PC? That would be strange indeed. I thought the floppy drive in Compact's were regular PC 3-mode drives with some extra features, only the X68000 BIOS was written to only recognize and use 1.2mb formatted disks. Then again it could explain why sector 0 always came up bad when trying to align my head using a 1.44mb formatted disk.

But if 1.44mb is no good then what are you supposed to configure the drive as in BIOS? A 1.2mb 5.25" drive? Or just leave it as a 1.44mb drive in BIOS, while turning on 3-mode functionality and insert 1.2mb formatted disks for head alignment?

I guess I could try all of the above once I get home.

[caius]

You mean that Compact floppy drives are incapable of reading 1.44mb formatted disks out of the box even when connected to a PC?

I only know for sure that they can't read under Human OS a  1.44 MB formatted disk without any specific driver

That would be strange indeed. I thought the floppy drive in Compact's were regular PC 3-mode drives with some extra features, only the X68000 BIOS was written to only recognize and use 1.2mb formatted disks. Then again it could explain why sector 0 always came up bad when trying to align my head using a 1.44mb formatted disk.

But if 1.44mb is no good then what are you supposed to configure the drive as in BIOS? A 1.2mb 5.25" drive? Or just leave it as a 1.44mb drive in BIOS, while turning on 3-mode functionality and insert 1.2mb formatted disks for head alignment?

I guess I could try all of the above once I get home.

Good question, maybe I'd try to leave it as 1.44MB drive in BIOS but let's try other setting, too.

[kamiboy]

So, which is setup for the FDR program?Is there the need of a previous 1.2 formatted disk?

P.S.
I want to try this program with my four CompacXVI FDD but first I ahae to change that secret capacitor since I was not yet able to separe the two assemblies

Here, this should help.

X68000 Compact floppy top part diassembly

[caius]

Thanks for the video, I'm going to try.

[kamiboy]

Dont be afraid to use a bit of force, these Compact floppies like it rough.

[kamiboy]

An update with my findings.

It seems FDR cannot determine the disk type of 1.44mb formatted disks whith Compact drive.

It "can" determine the format of 1.25mb formatted disks that I had rolled on my USB floppy drive via XP, but no matter where I put the head all secrors come up as fatal.

If, however, I configure a regular 3-mode floppy drive as a 5.25" 1.2mb drive in PC bios and then try disks formatted on that config on a Compact floppy with FDR then I can align the head so every sector comes up as being good.

Funny thing is even if FDR can read every sector of the disk DOS still does not recognize it as being valid. It thinks there is a 360k disk in there.

There is something funky going on here, and I suspect it has to do with the way we've wired the Compact drive to the PC.

It is worth noting that I have good reason to belive the 1.2mb disks one can write via old school DOS once configuring a 3-mode drive as a 5.25" 1.2mb drive are not the same as the 1.25mb disks written via the format command in XP.

I suspect this because in old school DOS when trying to write XDF images to 1.2mb formatted disks using rawrite3 results in adress not found errors near the end of the write process.

Anyhow, I am currently trying to install XP on this PC in order to try to write some X68000 style floppies and whether the problem might not be with the USB floppy written files.

[kamiboy]

Good news everyone, looks like that previous calibration did the trick.

My Compact can now boot Human68K from a 1.25mb floppy written via my USB floppy drive.

Here is the convoluted and only way I know how to do exactly that using a setup similar to mine.

What you need:

A DOS PC with an 3.5" 3-mode floppy drive.

The compact floppy drive needing to have its head aligned with an floppy ribbon cable connected to it using the latest pin diagram above.

A 3.5" 1.44mb diskette.

Step one: Enter your PC BIOS, turn on 3-mode and configure your drive as an 1.2mb 5.25" drive.

Step two: Enter DOS and format your floppy as a 1.2mb disk. You can use this command to do exactly that: "format a: /F:1.2 /U"

Step three: Set Compact Floppy jumper to Drive 1, connect it to your PC, and configure BIOS such that your floppy drive is on B: while retaining its type as 5.25" 1.2mb.

Step four: Boot PC, insert the 1.2mb formatted disk and start FDR to do head alignment.

Once you have the head aligned so FDR finds no bad sectors then you are done. Now once back in the Compact the floppy drive should be able to boot X68000 floppies written with a USB drive.

So far as I understand using floppies formatted for X68000 or 1.44mb formatted disks to do head alignment via FDR do not work on the Compact floppy. FDR does not recognize 1.44mb floppies and for X68000 floppies it must not understand the structure because it reads every sector as being bad even if your floppy head is perfectly aligned. A 1.2mb DOS formatted floppy is one of your only options. I think I managed to format either a 720k floppy also by taping one of its holes and formatting it on a regular floppy drive.

If you want to use 720k drives remember to remove the tape before inserting it into the Compact drive or it will be spat out.

I personally used a 1.2mb floppy to align the head, so I can attest to how well a 720k floppy works for that purpose, at the very least it seemed that FDR could read some clusters on such a floppy like on a 1.2mb floppy.

[caius]

Good news everyone, looks like that previous calibration did the trick.

My Compact can now boot Human68K from a 1.25mb floppy written via my USB floppy drive.

Good news!I think we must stick this in the Wiki

Here is the convoluted and only way I know how to do exactly that using a setup similar to mine.

What you need:

A DOS PC with an 3.5" 3-mode floppy drive.

The compact floppy drive needing to have its head aligned with an floppy ribbon cable connected to it using the latest pin diagram above.

A 3.5" 1.44mb diskette.

Step one: Enter your PC BIOS, turn on 3-mode and configure your drive as an 1.2mb 5.25" drive.

Step two: Enter DOS and format your floppy as a 1.2mb disk. You can use this command to do exactly that: "format a: /F:1.2 /U"

Step three: Set Compact Floppy jumper to Drive 1, connect it to your PC, and configure BIOS such that your floppy drive is on B: while retaining its type as 5.25" 1.2mb.

Step four: Boot PC, insert the 1.2mb formatted disk and start FDR to do head alignment.

Once you have the head aligned so FDR finds no bad sectors then you are done. Now once back in the Compact the floppy drive should be able to boot X68000 floppies written with a USB drive.

So far as I understand using floppies formatted for X68000 or 1.44mb formatted disks to do head alignment via FDR do not work on the Compact floppy. FDR does not recognize 1.44mb floppies and for X68000 floppies it must not understand the structure because it reads every sector as being bad even if your floppy head is perfectly aligned. A 1.2mb DOS formatted floppy is one of your only options. I think I managed to format either a 720k floppy also by taping one of its holes and formatting it on a regular floppy drive.

If you want to use 720k drives remember to remove the tape before inserting it into the Compact drive or it will be spat out.

I personally used a 1.2mb floppy to align the head, so I can attest to how well a 720k floppy works for that purpose, at the very least it seemed that FDR could read some clusters on such a floppy like on a 1.2mb floppy.

So, from what I understood, calibration with FDR is possible ONLY using a  previously 1.2MB formatted disk under DOS with a 3-mode 3.5" floppy and not a 1.2MB formatted disk with a USB drive under XP.

[kamiboy]

The thing to note is that 1.25mb (or more precisely 1.23mb) disks written under XP with the command below are not recognized by DOS, or even windows. They are in a weird nonestandard format that is not understood.

"format a: /fs:fat /v: /a:1024 /t:77 /n:8 /y"

When FDR tries to analyze such a disk using a Compact drive it prolly thinks it is a standard 1.2mb formatted disk, not a strange and nonstandard 1.23mb disk and therefore it sees bad clusters everywhere. That makes x68000 disks unsuitable for head alignment.

Anywaste that is my theory.

Perhaps you do not need DOS to write standard 1.2mb disks. Maybe you can write one in XP using a USB drive, I am not sure. You would need to hit the right set of format commands though.

All I know for sure is 1.2mb disks are easy to make under DOS, just configure your drive as a 1.2mb 5.25" drive and format your disk. I'll leave it to you gents to figure out how to write standard 1.2mb disks under XP.

[caius]

The thing to note is that 1.25mb (or more precisely 1.23mb) disks written under XP with the command below are not recognized by DOS, or even windows. They are in a weird nonestandard format that is not understood.

"format a: /fs:fat /v: /a:1024 /t:77 /n:8 /y"

I use this syntax under XP with a USB floppy drive:

FORMAT X: /A:1024 /T:77 /N:8 /U

[kamiboy]

That syntax does the same. Formats a 1.23 X68000 style floppy.

[kamiboy]

Among the options in SWITCH.X I see something about ramdisk and S-RAM.

I know S-RAM is 64k big, so is it possible to install a very basic Human68K to S-RAM and route the machine to boot off of it instead of having to boot off of a floppy every time?

Could be a nice fail safe in case the floppy drive goes bad again.