18 May
2013
18 May
'13
4:11 p.m.
On 5/18/2013 3:39 PM, allison wrote:
OH and before I hear whinging about 12 bit systems
needed 12 bit
storage... you can easily pack two words to 3bytes or just use two
bytes and only 6bits of each. Horrific then but storage is cheap now
(for modern stuff). Also for PDP8 a CF in IDE mode is 16bits wide,
and tossing the top 4 bits is not criminal and the CF will not care.
Actually I think fitting a 12-bit word into two bytes of disk is really
sensible. My PDP8 FPGA used the same bits-on-disk format as SIMH and can
use any of the available PDP8 SIMH disk images without modification. It
also makes transferring files between a PC and the PDP8 FPGA trivial. I
don't miss kermit. An SD card is a nice removable media - kinda like a
disk pack that won't break your foot if you drop it.
At less than 5 dollars for a 4 GB SD Card, who cares about packing
efficiency?
Rob.