[Simh] PDP-10/RP06 Disk Image Size

[Rob Doyle]

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/