Re: [Simh] PDP-10/RP06 Disk Image Size
On 13-Apr-15 01:21, khandy21yo wrote: Bad blocks No. Bad blocks for MASSBUS disks are within the non-maintenance cylinders, and tracked in the BAT blocks. See my previous note for the correct explanation. For MSCP disks, spare blocks (a.k.a. the RCT that the controller uses replace bad blocks) are indeed allocated above the LBN space. But they are separate from maintenance cylinders and are transparent to the OS addressing. More or less. MSCP is layered and has various implementation options. But that's beyond the scope of the OP's question. This communication may not represent my employer's views, if any, on the matters discussed. smime.p7s Description: S/MIME Cryptographic Signature ___ Simh mailing list Simh@trailing-edge.com http://mailman.trailing-edge.com/mailman/listinfo/simh
Re: [Simh] PDP-10/RP06 Disk Image Size
On 13-Apr-15 01:07, Rob Doyle wrote: I'm designing an RH11 disk controller for my KS10 FPGA. I'd like to use the SIMH data format for the media. I noticed that an RP06 disk image from SIMH is 315,187,200 bytes. Assuming an RP06 has 815 cylinders, 19 heads, 20 sectors (confirmed in SIMH code) - I calculate that disk image should be 317,132,800 bytes. If use 810 cylinders (instead of 815), I get the size of the of the image file. SIMH doesn't pack data: there are 128 words per sector and each word occupies 64-bits or 8 bytes. Therefore a sector is 1024 bytes. What's am I missing? Maintenance mode. The 5 highest cylinders of an RP06 are reserved for maintenance operations - providing a place for diagnostics to do writes and reads without touching the filesystem. This is a software convention; the hardware doesn't have any special support for this (though MSCP controllers do.) The number of maintenance cylinders was established for each drive type. SimH won't have any reason to seek to them unless you run a timesharing diagnostic that acesses these cylinders, which you probably haven't. So your host OS hasn't set EOF out there. There are special system calls that allow access under timesharing; e.g. for TOPS-10, SU.SMN is set in the SUSET. UUO to allow access to the maintenance cylinders. From rhxkon.mac, the geometry tables: | ||;BLOCKS PER UNIT|| || ||BLKPRU:DEC154280;(RP04/05) 406 CYLINDERS|| ||DEC307800;(RP06) 810 CYLINDERS|| ||DEC123150;(RM03) 821 CYLINDERS|| ||DEC865504;(RP07) 629 CYL, 32 SURF, 43 SECT|| || ||;BLOCKS PER UNIT IN MAINTENANCE MODE|| || ||BLKPUM:DEC156180;(RP04/RP05) 411 CYLINDERS|| ||DEC309700;(RP06) 815 CYLINDERS|| ||DEC123450;(RM03) 823 CYLINDERS|| ||DEC866880;(RP07) 630 CYLINDERS|| || ||;BLOCKS PER UNIT IN COMPATIBILITY MODE|| || ||BLKPUC:DEC171798;(RP04/RP05) 22*19*411|| ||DEC340670;(RP06) 22*19*815|| ||DEC131680;(RM03) 32*5*823|| ||0;(RP07) NO COMPATIBILITY MODE|| || ||;BLOCKS PER TRACK,,BLOCKS PER CYLINDER|| || ||BLKPTC:XWD^D20,^D380;(RP04)|| ||XWD^D20,^D380;(RP06)|| ||XWD^D30,^D150;(RM03)|| ||XWD^D43,^D1376;(RP07)|| | For TOPS-20, IIRC, you get to use DSKOP%. Stand-alone diagnostics knew to restrict their operations to the maintenance cylinders unless told by the operator that scribbling was OK (a scratch pack is mounted). This communication may not represent my employer's views, if any, on the matters discussed. smime.p7s Description: S/MIME Cryptographic Signature ___ Simh mailing list Simh@trailing-edge.com http://mailman.trailing-edge.com/mailman/listinfo/simh
[Simh] PDP-10/RP06 Disk Image Size
I'm designing an RH11 disk controller for my KS10 FPGA. I'd like to use the SIMH data format for the media. I noticed that an RP06 disk image from SIMH is 315,187,200 bytes. Assuming an RP06 has 815 cylinders, 19 heads, 20 sectors (confirmed in SIMH code) - I calculate that disk image should be 317,132,800 bytes. If use 810 cylinders (instead of 815), I get the size of the of the image file. SIMH doesn't pack data: there are 128 words per sector and each word occupies 64-bits or 8 bytes. Therefore a sector is 1024 bytes. What's am I missing? Rob -- KS10 FPGA Project at: http://www.techtravels.org/KS10FPGA/ ___ Simh mailing list Simh@trailing-edge.com http://mailman.trailing-edge.com/mailman/listinfo/simh
Re: [Simh] PDP-10/RP06 Disk Image Size
Bad blocks Original message From Rob Doyle radioe...@gmail.com Date: 04/12/2015 11:07 PM (GMT-07:00) To simh@trailing-edge.com Subject [Simh] PDP-10/RP06 Disk Image Size I'm designing an RH11 disk controller for my KS10 FPGA. I'd like to use the SIMH data format for the media. I noticed that an RP06 disk image from SIMH is 315,187,200 bytes. Assuming an RP06 has 815 cylinders, 19 heads, 20 sectors (confirmed in SIMH code) - I calculate that disk image should be 317,132,800 bytes. If use 810 cylinders (instead of 815), I get the size of the of the image file. SIMH doesn't pack data: there are 128 words per sector and each word occupies 64-bits or 8 bytes. Therefore a sector is 1024 bytes. What's am I missing? Rob -- KS10 FPGA Project at: http://www.techtravels.org/KS10FPGA/ ___ Simh mailing list Simh@trailing-edge.com http://mailman.trailing-edge.com/mailman/listinfo/simh___ Simh mailing list Simh@trailing-edge.com http://mailman.trailing-edge.com/mailman/listinfo/simh
