Hello , I have a problem setting drive/disk parameters with setfdprm ; eg: 'setfdprm /dev/fd0 ss dd sect=26 cyl=40 ssize=128' ; then 'getfdprm' responds with : 'SS DD size=260 sect=24 ssize=128' ; in which 'size=' would be '250' the correct value ; If I do a 'dd' , indeed I only get these 24 sectors outof the 26 each sector ; luckyly , using 'fdrawcmd' did the job - but 'dd' would be so much more elegant . In fact I found that I only could set 'sect' to 16,20,24,... ; I checked against different FDC's . What is wrong ? Anyone ? Regards .
Jurgen Kemmink wrote:
Hello ,
I have a problem setting drive/disk parameters with setfdprm ; eg: 'setfdprm /dev/fd0 ss dd sect=26 cyl=40 ssize=128' ;
then 'getfdprm' responds with : 'SS DD size=260 sect=24 ssize=128' ; in which 'size=' would be '250' the correct value ;
If I do a 'dd' , indeed I only get these 24 sectors outof the 26 each sector ; luckyly , using 'fdrawcmd' did the job - but 'dd' would be so much more elegant .
In fact I found that I only could set 'sect' to 16,20,24,... ; I checked against different FDC's . What is wrong ? Anyone ?
Regards .
The floppy driver internally represents the tracksize as a multiple of 512 byte units... which means that if the physical sector size is 128 bytes, only numbers that are divisible by 4 are supported. Regards, Alain
On Sunday 27 December 2009, Alain Knaff wrote:
Jurgen Kemmink wrote:
Hello ,
I have a problem setting drive/disk parameters with setfdprm ; eg: 'setfdprm /dev/fd0 ss dd sect=26 cyl=40 ssize=128' ;
then 'getfdprm' responds with : 'SS DD size=260 sect=24 ssize=128' ; in which 'size=' would be '250' the correct value ;
If I do a 'dd' , indeed I only get these 24 sectors outof the 26 each sector ; luckyly , using 'fdrawcmd' did the job - but 'dd' would be so much more elegant .
In fact I found that I only could set 'sect' to 16,20,24,... ; I checked against different FDC's . What is wrong ? Anyone ?
Regards .
The floppy driver internally represents the tracksize as a multiple of 512 byte units... which means that if the physical sector size is 128 bytes, only numbers that are divisible by 4 are supported.
Regards,
Alain
If I can butt into this thread, that just plain sucks. OS-9's disk format has been 18 each 256 byte sectors for at least 25 years. Tandy hard coded it to 35 tracks starting with track zero, and just one side in rsdos, but we've now worked around every limit but the 256 byte sector limit. Even that has workarounds so we can read and write pc formatted disks. But its a cobble job, somewhat like watching paint dry. 18 months ago, running fedora 6, I could format a disk on the coco, bring it up here, set the floppy to 256 byte sectors at 18/track, use dd to write an image of that disk on this linux box, take it back to the coco and read it perfectly. That was without the zero- based argument from another thread. Now I can't make dd access the disk to do anything with the current kernels floppy driver, no reads or write are completed, even partially. But it reads a messydos disk perfectly. But in the FC6 install, I recall I had to use fdutils-5.4, 5.5 didn't work. Now neither work, I've built both from the tarballs. Sorry for butting in but that limit you describe is a new one to me, and may explain why I once could but now can't handle an os-9 disk. Is this limit a new one? -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) There's another way to survive. Mutual trust -- and help. -- Kirk, "Day of the Dove", stardate unknown
Gene Heskett wrote:
On Sunday 27 December 2009, Alain Knaff wrote:
Jurgen Kemmink wrote:
Hello ,
I have a problem setting drive/disk parameters with setfdprm ; eg: 'setfdprm /dev/fd0 ss dd sect=26 cyl=40 ssize=128' ;
then 'getfdprm' responds with : 'SS DD size=260 sect=24 ssize=128' ; in which 'size=' would be '250' the correct value ;
If I do a 'dd' , indeed I only get these 24 sectors outof the 26 each sector ; luckyly , using 'fdrawcmd' did the job - but 'dd' would be so much more elegant .
In fact I found that I only could set 'sect' to 16,20,24,... ; I checked against different FDC's . What is wrong ? Anyone ?
Regards . The floppy driver internally represents the tracksize as a multiple of 512 byte units... which means that if the physical sector size is 128 bytes, only numbers that are divisible by 4 are supported.
Regards,
Alain
If I can butt into this thread, that just plain sucks. OS-9's disk format has been 18 each 256 byte sectors for at least 25 years. Tandy hard coded it to 35 tracks starting with track zero, and just one side in rsdos, but we've now worked around every limit but the 256 byte sector limit. Even that has workarounds so we can read and write pc formatted disks. But its a cobble job, somewhat like watching paint dry. 18 months ago, running fedora 6, I could format a disk on the coco, bring it up here, set the floppy to 256 byte sectors at 18/track, use dd to write an image of that disk on this linux box, take it back to the coco and read it perfectly. That was without the zero- based argument from another thread.
Now I can't make dd access the disk to do anything with the current kernels floppy driver, no reads or write are completed, even partially. But it reads a messydos disk perfectly.
But in the FC6 install, I recall I had to use fdutils-5.4, 5.5 didn't work. Now neither work, I've built both from the tarballs.
Sorry for butting in but that limit you describe is a new one to me, and may explain why I once could but now can't handle an os-9 disk. Is this limit a new one?
This limit has existed since sub-512 byte sectors have been supported.
participants (3)
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Alain Knaff -
Gene Heskett -
Jurgen Kemmink