On Sun, 12 Apr 2015, 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.
Add RP07 support too!
I noticed that an RP06 disk image from SIMH is 315,187,200 bytes.
Wait, what? Isn't an RP06 around ~180M?
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.
http://www.columbia.edu/cu/computinghistory/rp06.html 128 Words/sector 20 Sectors/track 19 Tracks/cylinder 815 Cylinders/pack Number of heads: 20 What am _I_ missing? ;)
If use 810 cylinders (instead of 815), I get the size of the of the image file.
Is your file system considering the file to be "sparse" by chance?
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
-- Cory Smelosky http://gewt.net Personal stuff http://gimme-sympathy.org Projects _______________________________________________ Simh mailing list Simh@trailing-edge.com http://mailman.trailing-edge.com/mailman/listinfo/simh
