× The internal search function is temporarily non-functional. The current search engine is no longer viable and we are researching alternatives.
As a stop gap measure, we are using Google's custom search engine service.
If you know of an easy to use, open source, search engine ... please contact support@midrange.com.


  • Subject: Re: why the 16meg space size limit?
  • From: "Steve Richter" <srichter@xxxxxxxxxxxxx>
  • Date: Mon, 21 May 2001 13:18:55 -0400

 
 
====> a system pointer to a usrspc (actually to any) object is constructed like this (each character=4-bits):
KAAAA000 00000000 SSSSSSSS SS00TTAA
Roughly K is the type of the pointer, the As are authority bits, the 0s are zeroes, the Ss are a 'segment'
address, and the Ts are the object type. The object starts at address SSSSSSSSSS000000. Note, that
the low-order 24 bits are zero. When you create a spacepointer from the system pointer, these low-order
24 bits contains an offset within the space, hence the 26Mb limitation.
 
 
So, could a teraspace pointer have a diff "k" value and shift the segment value over a byte or two?
KAAAA000 0000SSSS SSSSSS00 0000TTAA
Then use the addr xlate tables or whatever built into the cpu to provide a contiguous looking group of segments?  The intel 386 architecture solved the segment problem with paging and addr xlate support built into the cpu.  no?  I am not sure.
 
Steve
 
 
 
 
 
 

As an Amazon Associate we earn from qualifying purchases.

This thread ...

Follow-Ups:

Follow On AppleNews
Return to Archive home page | Return to MIDRANGE.COM home page

This mailing list archive is Copyright 1997-2024 by midrange.com and David Gibbs as a compilation work. Use of the archive is restricted to research of a business or technical nature. Any other uses are prohibited. Full details are available on our policy page. If you have questions about this, please contact [javascript protected email address].

Operating expenses for this site are earned using the Amazon Associate program and Google Adsense.