[Freedos-kernel] Fwd: FreeDOS kernel disk routines
This is a forwarded message From: Jose Antonio Senna Subject: FreeDOS kernel disk routines ===8==Original message text=== Excuse me for sending this directly to you, but I am still unable to post on Freedos lists. I do not know who (if anyone) mantains the FreeDOS kernel disk routines. If it is not you, please pass this mail to the appropriate person. The problem I found is: My computer BIOS INT 13 is able to access up to 4096 cylinders in a hard disk, by using bits 6 -7 of DH in INT 13 requests as bits 10-11 of cylinder number. This BIOS variant is documented in Brown and Kyle interrupts list. However,FreeDOS hooks INT 13 and,in doing so,rolls over any cylinder number modulo 1024,that is,if I make a request to access cylinder 1024,it does not report any error,but I get cylinder 0, and so on. FreeDOS is not the only DOS to have this problem. Is it too difficult to solve ? I thank you for your attention JAS ===8===End of original message text=== my comment: how are these disks/BIOS variants detected ? I have a faint memory of these translating BIOS's, but can't find it in RBIL. IMO the kernel shouldn't touch partitions that are to big to handle (1024 cylinders), unless LBA is detected. tom --- This SF.Net email is sponsored by: Sybase ASE Linux Express Edition - download now for FREE LinuxWorld Reader's Choice Award Winner for best database on Linux. http://ads.osdn.com/?ad_id=5588alloc_id=12065op=click ___ Freedos-kernel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/freedos-kernel
Re: [Freedos-kernel] Fwd: FreeDOS kernel disk routines
Hi! 6--2004 16:13 [EMAIL PROTECTED] (tom ehlert) wrote to [EMAIL PROTECTED]: te From: Jose Antonio Senna te ===8==Original message text=== te Excuse me for sending this directly to you, but I am still unable to post te on Freedos lists. te I do not know who (if anyone) mantains the FreeDOS kernel disk routines. te If it is not you, please pass this mail to the appropriate person. te The problem I found is: te My computer BIOS INT 13 is able to access up to 4096 cylinders in a hard te disk, te by using bits 6 -7 of DH in INT 13 requests as bits 10-11 of cylinder te number. If so, then this is non-standard and this completely prohibits LBA (with up to 256/255 heads). te This BIOS variant is documented in Brown and Kyle interrupts list. Ralf Brown not documents such API deviation (or I miss something?). te However,FreeDOS hooks INT 13 and,in doing so,rolls over any cylinder te number modulo 1024, that is,if I make a request to access cylinder 1024,it te does not report any error,but I get cylinder 0, and so on. FreeDOS _doesn't_ hooks INT 13. See main.c:setup_int_vectors() for list of hooked vectors. te FreeDOS is not the only DOS to have this problem. May you quote code fragment, which works under other OSes (which?) and doesn't works under FD? te Is it too difficult to solve ? te ===8===End of original message text=== te my comment: te how are these disks/BIOS variants detected ? te I have a faint memory of these translating BIOS's, but can't find it te in RBIL. te IMO the kernel shouldn't touch partitions that are to big to handle (1024 cylinders), unless LBA is detected. --- This SF.Net email is sponsored by: Sybase ASE Linux Express Edition - download now for FREE LinuxWorld Reader's Choice Award Winner for best database on Linux. http://ads.osdn.com/?ad_idU88alloc_id065op=click ___ Freedos-kernel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/freedos-kernel
Re: [Freedos-kernel] Fwd: FreeDOS kernel disk routines
On Sat, 6 Nov 2004, tom ehlert wrote: However,FreeDOS hooks INT 13 No, if anything hooks INT 13 it could be LBACACHE but the kernel does not (it should but for different reasons -- see int2f/ah=13 in RBIL). how are these disks/BIOS variants detected ? I have a faint memory of these translating BIOS's, but can't find it in RBIL. RBIL D-1302 INT 13 - DISK - READ SECTOR(S) INTO MEMORY [...] AWARD AT BIOS and AMI 386sx BIOS have been extended to handle more than 1024 cylinders by placing bits 10 and 11 of the cylinder number into bits 6 and 7 of DH Probably a rare breed of machines. For most bit 6 7 of DH mean bit 6 and 7 of the (translated) head number. I have no idea how to distinguish this meaning. My 386 SX only had 80 MB hard disk space, which was far below the first problematic barrier of 1024*16*63*512=512MB IMO the kernel shouldn't touch partitions that are to big to handle (1024 cylinders), unless LBA is detected. Agreed. That's what it does today. Bart --- This SF.Net email is sponsored by: Sybase ASE Linux Express Edition - download now for FREE LinuxWorld Reader's Choice Award Winner for best database on Linux. http://ads.osdn.com/?ad_id=5588alloc_id=12065op=click ___ Freedos-kernel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/freedos-kernel
Re: [Freedos-kernel] Fwd: FreeDOS kernel disk routines
Hi! 7--2004 09:24 [EMAIL PROTECTED] (Bart Oldeman) wrote to [EMAIL PROTECTED]: BO My 386 SX only had 80 MB hard disk space, which was far below the BO first problematic barrier of 1024*16*63*512=512MB 1024*16*63*512=504Mb (or 528 Mb, as this counted by disk manufacturers). --- This SF.Net email is sponsored by: Sybase ASE Linux Express Edition - download now for FREE LinuxWorld Reader's Choice Award Winner for best database on Linux. http://ads.osdn.com/?ad_idU88alloc_id065op=click ___ Freedos-kernel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/freedos-kernel
