Date   : Fri, 25 Jan 1991 01:24:06 GMT
From   : zephyr.ens.tek.com!tektronix!percy!nosun!techbook!fzsitvay@uunet.uu.net (Frank Zsitvay)
Subject: 8 meg limit

In article <4314@mentor.cc.purdue.edu> wilker@gauss.math.purdue.edu.UUCP
(Clarence Wilkerson) writes:
>I believe that the 8meg limit is set in the coding of
>the BDOS, and inforced in the BIOS in the sense that
>certain scratch ram in the BIOS data area has a preset
>size.
>   I think several replacement BDOS clones, e.g.
>DOSPLUS, offer larger maximum logical disk size.
>   There would be some perfomance penalties for
>using larger sizes, namely more directory entries
>to check or larger logical block sizes.
>Clarence Wilkerson

   well, not really.   it is limited by the directory structure that is at 
the heart of all cp/m disk operations.  cp/m only allows for a maximum of
65536 128 byte blocks.  that is the maximum size of a file, or a whole
disk.
 
   there is a built in mechanism in cp/m to allow the creation of 
partitions on a single physical disk.
 
    dosplus is essentially a different operating system than cp/m,
and it allows a larger total disk space through a somewhat revamped
directory structure.
 
   zcpr3 and zsystem do it through other techniques.

-- 
fzsitvay@techbook.COM - but don't quote me on that....

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