Ram Memory Usage

3D Laser Etched Art Crystal Paperweights $5.95
Fake Security Camera Moves and Blinks $6.95
Spanish Language DVDs (En Espanol) $4.95
Create Window Website
Add Right Click New Folder to Windows Explorer
How to Install and Run Regclean
How to Install PowerToys (Tweak UI) and Kernel PowerToys
32 bit Cyclic Redundancy Check Source Code for C++
Floppy Drive Access Bug
Restart Windows with a Shortcut
32 Bit CRC File Calculation
RegClean ReadMe.txt
Update Comctl32.dll if You Don't Have MSIE 5.x
How to Verify CRC-32 Numbers
32 Bit CRC Text Calculation
Ram Memory Usage
How to Update Win95 to Win95a
Create Window Programming Section
Freeware by -RAE-
Logon and Password Problems
ReStart Setup Program Source Code
Open Two Explorer Windows at Once
ReStart Setup Program Help
Create Window Win Info Section
Wait Text
The -RAE- Website
Create Window Freeware Section
Use FIND to Locate File References
Hot Key Assignment Bug
NoDocs Text
ShortTop Information
Question:      Why do System Monitor and Norton Utilities report that I have almost no free RAM available?

Answer:      Physically, memory includes a variable-size disk cache which generally uses most of the free memory, but automatically reduces in size as physical memory is needed.  Therefore, most of the physical memory is always in use.

VCACHE and CDFS Supplemental Cache (excerpt from the Win95 Resource Kit)

     The 32-bit VFAT works in conjunction with a 32-bit, protected-mode cache driver (VCACHE), and replaces and improves on the 16-bit real-mode SMARTDrive disk cache software provided with MS-DOS and Windows 3.1. The VCACHE driver uses an improved caching algorithm over SMARTDrive to cache information read from or written to a disk drive, and results in improved performance for reading information from the cache. Also, the VCACHE driver is responsible for managing the cache pool for CDFS, and the 32-bit network redirectors.

     Another big improvement in VCACHE over SMARTDrive is that the memory pool used for the cache is dynamic and is based on the amount of available free system memory. Users no longer need to allocate a block of memory to set aside as a disk cache; the system automatically allocates or deallocates memory used for the cache based on system use. The performance of the system also scales better than earlier versions of Windows, due to the intelligent cache use. The 32-bit protected-mode CDFS implemented in Windows 95 provides improved CD-ROM access performance over the real-mode MSCDEX driver in Windows 3.1 and is a full 32-bit ISO 9660 CD file system. The CDFS driver replaces the 16-bit real-mode MSCDEX driver, and it features 32-bit protected-mode caching of CD-ROM data. If MSCDEX is specified in the userís AUTOEXEC.BAT when Windows 95 is installed, the 32-bit CDFS driver is used instead.

     CDFS has a larger and smarter cache than MSCDEX, optimized just for CD-ROMs and separate from VCACHE. The CDFS driver cache is dynamic and shares the cache memory pool with the 32-bit VFAT driver, requiring no configuration or static allocation on the part of the user. CDFS reads ahead in parallel with the application so that multimedia presentations play back more smoothly than with earlier versions of Windows. Because CDFS uses a separate cache, the cache memory can be swapped out to the hard disk when CD-ROM activity pauses. This gives applications more room to run and protects the main hard disk cache from being flushed out whenever a very large multimedia stream is played back.

     The supplemental cache size for CDFS is used to hold path table, directory, and file information. This particular cache is used to improve CD streaming and to reduce seek latency as effectively as possible with a moderately sized cache. This means that the cache is more complex, using smart priority-based caching schemes to achieve results optimized for CD-ROMs.

PC Magazine Utilities and source code written by -RAE-
icon ClipTrak Clipboard Organizer
icon DaysEase Calendar

This page is located online at:
Ram Memory Usage
Copyright © 2000 - 2010 Richard A. Ellingson