[Coco] Re: Re: Re: Disk Basic and 512 byte block floppies.
Theodore Evans (Alex)
alxevans at concentric.net
Wed Jan 21 22:37:10 EST 2004
On Jan 21, 2004, at 11:34 AM, KnudsenMJ at aol.com wrote:
> In a message dated 1/20/04 10:06:38 PM Eastern Standard Time,
> alxevans at concentric.net writes:
>> All CP/M disk formats use virtual 128 byte sectors, and a few (very
>> few) use physical 128 byte sectors.
> ISTR that in CP/M, the 128th byte of each sector points to the next
> sector in
> the file, so you get only 127 bytes per sector, and some real
> to screw up your file system :-) Also, this would limit a disk to 256
> total, so maybe I'm not remembering quite right. --Mike K.
Actually CP/M uses a FAT similar to Disk BASIC, though it does lack any
way to indicate a partial sector. All files are 128*N bytes in length
(though the EOF character ^Z does serve to terminate some types of
files). This at least part of the reason why Xmodem (aka Modem7 or
RCPM) has the characteristics that it does.
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