Floppy image

Linux ? They used it for somethin like bootable CDR maybe ? But i dont envy you , needing to hunt docs on Linux !! They boldly admitted , they would milk the Doc project til hell freezes over !!

It is a never ending project . But Why !!!!

I tried Linux , i could not learn to create images , i could not learn to program in C ,.........

Thats why i and the rest of the world went back to WXP ....

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Ed wrote:

I do not remember where I had it (it was 20 years ago), but it might have been in the data sheets of the upd765 of NEC; or in the MC6843 of Motorola; or may be in some Motorola application note. Hopefully these are some leads for a successful search....

Dimiter

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The data sheet for National Semiconductor's PC8477 controller chip has this information, in Fig. 4.1.

The problem with that data sheet is the unknown Gap3 and Gap4 information. What is their for a 1.44meg 3.5" floppy?

See

Gap 4 is not a written gap, it is the remainder of a track when all the sectors have been written and as such will depend on the speed of rotation of the drive.

--Rocky

PS did the CRC code help?

Like I mentioned in my former posting, I did this about 20 years ago, but incidentally I had the files with drive related definitions at hand, here they are for 3.5" HD and 5.25" HD drives with _256_ (not 512, I never made that) bytes per sector. I remember I had to experiment somewhat with the gaps, years later I found out that the way I had set them still worked fine on another drive which had 256 bytes per sector (a SCSI TEAC).

If you will implement also 256 bytes per sector - not that I can think of a reason why - these might be of some use.

IFEQ \0!.$F0-FD35GA - this is the 3.5" drive

• DRIVE TYPE FD35F - 80 TRACKS,TWO SIDES,HIGH DENSITY

• USED TRACK 0-29 WHICH PROVIDE THE 512K MDOS CAN HANDLE FCB $DF STEP RATE;HEAD UNLOAD TIME FCB +.DMA HEAD LOAD TIME AND DMA BIT FCB .CD - THE MFM BIT FCB * USED TRACK 0-29 WHICH PROVIDE THE 512K MDOS CAN HANDLE FCB $DF STEP RATE;HEAD UNLOAD TIME FCB $02+.DMA HEAD LOAD TIME AND DMA BIT FCB $40 .CD - THE MFM BIT FCB \0!.$3 .U - PHYSICAL DRIVE NUMBER FCB 1 .C - RE-RESTORE ALLOWED FCB 1 .H - TWO HEADS FCB $46 .R - LS PER SIDE FCB 1 .N - (LS PER PHYSICAL SECTOR)-1 FCB $23 .EOT - PSN OF EOT (ONE SIDE,NO #0) FCB $0E .GPL - GAP LENGTH FCB $FF .DTL - N>0 FCB 0 OFFSET TO PHYSICAL TRACK 0 FCB 1 STEP COUNT MULTIPLYER FCB 29 HIGHEST VALID TRACK NUMBER (I had these drives partitioned...) FCB 36 FORMAT MODE GAP LENGTH FCB FDCLK$ CLOCK/SPEED SEL.!. .U - PHYSICAL DRIVE NUMBER FCB 1 .C - RE-RESTORE ALLOWED FCB 1 .H - TWO HEADS FCB .R - LS PER SIDE FCB 1 .N - (LS PER PHYSICAL SECTOR)-1 FCB .EOT - PSN OF EOT (ONE SIDE,NO #0) FCB * USED TRACK 0-29 WHICH PROVIDE THE 512K MDOS CAN HANDLE FCB $DF STEP RATE;HEAD UNLOAD TIME FCB $02+.DMA HEAD LOAD TIME AND DMA BIT FCB $40 .CD - THE MFM BIT FCB \0!.$3 .U - PHYSICAL DRIVE NUMBER FCB 1 .C - RE-RESTORE ALLOWED FCB 1 .H - TWO HEADS FCB $46 .R - LS PER SIDE FCB 1 .N - (LS PER PHYSICAL SECTOR)-1 FCB $23 .EOT - PSN OF EOT (ONE SIDE,NO #0) FCB $0E .GPL - GAP LENGTH FCB $FF .DTL - N>0 FCB 0 OFFSET TO PHYSICAL TRACK 0 FCB 1 STEP COUNT MULTIPLYER FCB 29 HIGHEST VALID TRACK NUMBER (I had these drives partitioned...) FCB 36 FORMAT MODE GAP LENGTH FCB FDCLK$ CLOCK/SPEED SEL.E .GPL - GAP LENGTH FCB $FF .DTL - N>0 FCB 0 OFFSET TO PHYSICAL TRACK 0 FCB 1 STEP COUNT MULTIPLYER FCB 29 HIGHEST VALID TRACK NUMBER (I had these drives partitioned...) FCB 36 FORMAT MODE GAP LENGTH FCB FDCLK$ CLOCK/SPEED SEL.

• ENDC .....

• IFEQ * IFEQ \0!.$F0-FD55GB - this is the 5.25 , IIRC with the same values as the 3.5"!.$F0-FD55GB - this is the 5.25 , IIRC with the same values as the 3.5"

• DRIVE TYPE FD55GB - SECOND 40 TRACKS,TWO SIDES,360 RPM FCB $DF STEP RATE;HEAD UNLOAD TIME FCB +.DMA HEAD LOAD TIME AND DMA BIT FCB .CD - THE MFM BIT FCB * DRIVE TYPE FD55GB - SECOND 40 TRACKS,TWO SIDES,360 RPM FCB $DF STEP RATE;HEAD UNLOAD TIME FCB $02+.DMA HEAD LOAD TIME AND DMA BIT FCB $40 .CD - THE MFM BIT FCB \0!.$3 .U - PHYSICAL DRIVE NUMBER FCB 1 .C - RE-RESTORE ALLOWED FCB 1 .H - TWO HEADS FCB $34 .R - LS PER SIDE FCB 1 .N - (LS PER PHYSICAL SECTOR)-1 FCB $1A .EOT - PSN OF EOT (ONE SIDE,NO #0) FCB $0E .GPL - GAP LENGTH FCB $FF .DTL - BYTES PER SECTOR FCB 40 OFFSET TO PHYSICAL TRACK 0 FCB 1 STEP COUNT MULTIPLYER FCB 79 HIGHEST VALID TRACK NUMBER FCB 54 FORMAT MODE GAP LENGTH FCB FDCLK$ CLOCK/SPEED SEL.!. .U - PHYSICAL DRIVE NUMBER FCB 1 .C - RE-RESTORE ALLOWED FCB 1 .H - TWO HEADS FCB .R - LS PER SIDE FCB 1 .N - (LS PER PHYSICAL SECTOR)-1 FCB A .EOT - PSN OF EOT (ONE SIDE,NO #0) FCB * DRIVE TYPE FD55GB - SECOND 40 TRACKS,TWO SIDES,360 RPM FCB $DF STEP RATE;HEAD UNLOAD TIME FCB $02+.DMA HEAD LOAD TIME AND DMA BIT FCB $40 .CD - THE MFM BIT FCB \0!.$3 .U - PHYSICAL DRIVE NUMBER FCB 1 .C - RE-RESTORE ALLOWED FCB 1 .H - TWO HEADS FCB $34 .R - LS PER SIDE FCB 1 .N - (LS PER PHYSICAL SECTOR)-1 FCB $1A .EOT - PSN OF EOT (ONE SIDE,NO #0) FCB $0E .GPL - GAP LENGTH FCB $FF .DTL - BYTES PER SECTOR FCB 40 OFFSET TO PHYSICAL TRACK 0 FCB 1 STEP COUNT MULTIPLYER FCB 79 HIGHEST VALID TRACK NUMBER FCB 54 FORMAT MODE GAP LENGTH FCB FDCLK$ CLOCK/SPEED SEL.E .GPL - GAP LENGTH FCB $FF .DTL - BYTES PER SECTOR FCB 40 OFFSET TO PHYSICAL TRACK 0 FCB 1 STEP COUNT MULTIPLYER FCB 79 HIGHEST VALID TRACK NUMBER FCB 54 FORMAT MODE GAP LENGTH FCB FDCLK$ CLOCK/SPEED SEL.

• ENDC

Dimiter

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Ed wrote: