sock@gumby.UUCP (Isabella Ng) (07/11/86)
How does DESQVIEQ interact with the EMS, does it allocate memory equally to all programs run under QuarterDecks DESKQVIEW, if I run 9 programs simultaneously does it divide the memory equally ! Pleas Mail me if you have any views, Thanks in Advance ! Isabella
johnl@ima.UUCP (07/16/86)
In article <338@gumby.UUCP> sock@gumby.UUCP (Isabella Ng) writes: >How does DESQVIEQ interact with the EMS, does it allocate memory equally >to all programs run under QuarterDecks DESKQVIEW, if I run 9 programs >simultaneously does it divide the memory equally ! Each program that uses EMS asks for some expanded memory, usually when it starts up. There is no practical way to give expanded memory back short of exiting a program, so most programs seem to have heuistics like allocate 1/4 of the available expanded memory when it starts, and grab the other quarters as needed. Practically speaking, this means that the first program you load will get the largest fraction of your expanded memory. Programs that don't know about EMS won't ask for any and so won't get any assigned. >[ what about EMS vs. EEMS] The RAMPage EEMS system lets Desqview map expanded pages in and out of the regular 640K address space.* Desqview makes good use of this, and I have run multiple programs simultaneously, even though together they added up to well over a megabyte. If you don't have EEMS, it swaps programs in and out which works OK except that swapped out programs don't get swapped back in until you explicitly ask to restart them. If you have an Above Board, that's EMS rather than EEMS so the best you can do is to set up a RAM disk on the EMS and tell DesqView to swap there. * - It can only do the page swapping in addresses assigned to the RAMPage card, so to get the best use of EEMS and DesqView, you should pull the chips off the motherboard, except for the first row, and plug them into your RamPage card to maximize the amount of remappable memory. -- John R. Levine, Javelin Software Corp., Cambridge MA +1 617 494 1400 { ihnp4 | decvax | cbosgd | harvard | yale }!ima!johnl, Levine@YALE.EDU The opinions expressed herein are solely those of a 12-year-old hacker who has broken into my account and not those of any person or organization.
jrv@siemens.UUCP (07/17/86)
Levine@YALE.EDU write: >Each program that uses EMS asks for some expanded memory, usually when >it starts up. There is no practical way to give expanded memory back ^^^^^^^^^^^^^^^^ >short of exiting a program, ... From the point of view of a user this is true. From the programmers point of view this is not entirely true. If the expanded memory is no longer needed there is a function in the EMS to close the EMM handle and deallocate the pages of memory. Also, there is no reason that a single application could no call the memory handler and get several EMM handles as the need arises. Releasing them individually when no longer needed. The specification *suggests* that each application may one request at the beginning of the program, though this is not a requirement. There is no way to release a portion or increase the size of memory allocated once the EMM handle has been gotten. Jim Vallino Siemens Research and Technology Lab. Princeton, NJ {allegra,ihnp4,seismo,philabs}!princeton!siemens!jrv