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- ID:MS Memory Status Discussion
- Quarterdeck Technical Note #131
- by Bob Perry
-
- Q. What do the numbers in the Memory Status window mean?
-
- Q. Why does DESQview report 0K for Largest Available Expanded Memory?
-
- Q. Why does Total Memory for Expanded not report all my board memory?
-
- The Memory Status (MS.COM) program dynamically displays the current memory
- usage of your system at any given moment. It takes about 7K "overhead" to run
- this program. When you run Memory Status, the window shows three columns and
- three rows of numbers.
-
- The ROWS list the three main memory areas of interest:
-
- 1-Common Memory (in Bytes): Common Memory refers to the amount of memory
- in DESQview's Common Memory buffer, and generally should not be allowed
- to drop below 1,000 bytes. Allocations are made by running the SETUP
- program.
-
- 2-Conventional Memory (in Kilobytes, K): Conventional Memory refers to
- the memory available for you to run programs in the 0K-640K memory area
- of your computer. This consists of any type of memory your system uses
- to fill out to 640K.
-
- 3-Expanded Memory (in Kilobytes, K): Expanded Memory refers to memory
- supplied by expanded memory boards. Memory Status will not report
- expanded memory used for other purposes, such as to fill-out conventional
- memory, RAM disks, print spoolers or disk caches.
-
- The COLUMNS in Memory Status are useful in determining the current memory
- sizes of the following three areas:
-
- A. Total Memory: Total Memory refers to the total memory available on
- your system at the moment you started DESQview. Such things as device
- drivers, memory-resident programs and buffers (indeed, almost everything
- you might load in your CONFIG.SYS and AUTOEXEC.BAT files before DESQview)
- will cause the numbers in this column to be lower.
-
- B. Total Available: Total Available is the total memory available to
- store data and run programs at the current moment. These numbers are
- TOTAL numbers and do not reflect the size of any one program, which is
- shown in the third column.
-
- C. Largest Available: The third column, and perhaps the most useful
- one, tells you the largest area of contiguous memory available at the
- current moment to run a program. NOTE THAT YOU MUST SUBTRACT
- APPROXIMATELY 14K FROM THESE FIGURES TO ADD OR CHANGE A PROGRAM'S MEMORY
- SIZE. This is because DESQview needs about 14K to manage each
- application.
-
- The Largest Available amount of memory for Expanded Memory, which is the lower
- right corner figure in Memory Status, is useful because it determines the size
- of secondary programs that you can multitask (i.e., keep running at the same
- time as your conventional memory program) without swapping. Only expanded
- memory which conforms to EEMS (Enhanced Expanded Memory Specification) or EMS
- 4 (Expanded Memory 4.0 Specification) will result in a number in this
- location. No other expanded memory boards or boards with so-called EMS 4
- software drivers can be used for multitasking.
-
-
- ************************************************************************
- *This technical note may be copied and distributed freely as long as it*
- *is distributed in its entirety and it is not distributed for profit. *
- * Copyright (C) 1991 by Quarterdeck Office Systems *
- ************************ E N D O F F I L E *************************
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