home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Cream of the Crop 21
/
Cream of the Crop 21 (Terry Blount) (October 1996).iso
/
windows
/
vram100t.zip
/
README.TXT
< prev
next >
Wrap
Text File
|
1996-07-20
|
17KB
|
435 lines
========================
VRAMDIR 1.00
for Microsoft Windows 95
========================
Copyright 1996
Virtual Software Corporation
15016 SE 63 St.
Bellevue, WA 98006
http://accessone.com/~virtual/vramdir.htm
virtual@accessone.com
VRAMDIR is a dynamic 32-bit virtual RAM file system driver for
Windows 95.
A. Introduction
B. Advantages of VRAMDIR over Hard-disks
C. Advantages of VRAMDIR over RAM-disks
D. Advantages of VRAMDIR over Disk-Cache
E. Installation
F. Usage
G. Benchmarks
H. Where to Get the FREE Trial Version of VRAMDIR
I. Limit of the Trial Version
J. How to Order VRAMDIR
K. Technical Support
L. License and Disclaimer
============
A. Introduction
============
VRAMDIR is a dynamic 32-bit virtual RAM file system driver for
Windows 95. It is to replace RAM-disk and speed up hard-disk
related operations. VRAMDIR is over 30 times faster than hard-
disks, 5 times faster than RAM-disks, and 2 times faster than
disk-cache. VRAMDIR also keeps hard-disks less fragmented,
saves hard-disk wears and tears, and saves battery power on
notebook computers.
VRAMDIR does not pre-allocate any memory, and it has no
practical limit on the amount of files it can hold. No matter
how much RAM your system has, VRAMDIR puts it into more
efficient use and speeds up the system. If the system has more
than 32MB RAM, VRAMDIR prevents the RAM from being wasted; if
the system has less than 16MB RAM, it is important to use
VRAMDIR to increase system speed.
=====================================
B. Advantages of VRAMDIR over Hard-disks
=====================================
VRAMDIR is tens and thousands of times faster than hard-disks.
VRAMDIR creates file systems in Random Access Memory (RAM) to
simulate hard-disks.
In access time, RAM is thousands of times faster than hard-
disks. Locating an address in RAM takes 50-100ns, while
seeking to a sector on a hard-disk takes 5-20ms. So RAM access
is about 100,000 times faster.
In throughput, RAM is tens of times faster than hard-disk.
Reading/writing one block of data in RAM is about 20-100MB/s,
while on hard-disks it is 1-2MB/s. So RAM throughput is 10-100
times faster.
By using VRAMDIR file systems, file operations are tens and
thousands of times faster than hard-disks.
VRAMDIR keeps the hard-disks less fragmented. Without VRAMDIR,
temporary files scatter around on hard-disks. This can be
prevented by creating the temporary files in VRAMDIR. Less
fragmented hard-disks result in faster hard-disk access.
VRAMDIR saves wears and tears of hard-disks. Hard-disks have
mechanical parts and thus have much shorter life-spans than
RAM. When accessing files in VRAMDIR, hard-disks are not
accessed. Thus hard-disks are less probable to fail, and hard-
disks live longer, hence it is less likely to lose your data
on hard-disks.
VRAMDIR saves battery power on notebook computers. When hard-
disks are less often accessed because of VRAMDIR, less power
is consumed by hard-disks, and the battery runs longer.
=============================================
C. Advantages of VRAMDIR over RAM-Disk Utilities
=============================================
VRAMDIR is several times faster than RAM-disk utilities.
VRAMDIR is a 32-bit protected-mode Windows 95 native virtual
device driver (VxD), while RAM-disk utilities are 16-bit real-
mode DOS device drivers. With RAM-disks, Windows 95 needs to
switch forth and back between 16-bit real-mode and 32-bit
protected-mode. This very time consuming mode switching is
avoided in VRAMDIR. For example, when benchmarked against
RAMDRIVE, VRAMDIR is more than 4 times faster.
VRAMDIR is dynamic. When there is no file in VRAMDIR, VRAMDIR
does not allocate any memory. RAM-disks, on the other hand,
pre-allocate fixed amount of memory. Even when the memory is
not used by files on a RAM-disk, the memory is no longer
available to system and application programs. With VRAMDIR, no
extra memory is taken, more memory is available to the system,
and the system runs faster.
When more files need to be on RAM-disk than the fixed amount
pre-allocated, RAM-disk is not able to hold them. The
operation will fail, and your application or even the system
may crash as a result. With VRAMDIR, it expands on demand.
There is no practical limit on the number of files and the
size of files that can fit into VRAMDIR. (The limit is the
total amount of physical memory plus the free hard-disk space
in your system, which is even larger than what is available
without VRAMDIR, the free hard-disk space alone.)
VRAMDIR is virtual. VRAMDIR can return memory back to the
system, while RAM-disks can never do that. When other
applications need more memory, files in VRAMDIR can be saved
onto hard-disks and memory is returned to system. You never
need to worry about VRAMDIR using too much memory. VRAMDIR
makes sure that it always puts memory into the best use and
that the system runs as fast as possible.
VRAMDIR creates virtual file systems, while RAM-disks create
disk images on which to build FAT file systems. Disks are
block devices and have limitations. For example, on a disk
even when only 1-byte is used in a block, the rest is not
available to other files. RAM is different from disks. It is
not efficient to use RAM in the same block manner as disks.
FAT file system has further limitations. In RAM-disks, e.g.,
space needs to be pre-allocated for File Allocation Tables
(FAT), the block size and the number of entries in the root
directory, etc., needs to be pre-determined. VRAMDIR avoids
the limitations of block devices and the FAT system. VRAMDIRÆs
file system is virtual and much more efficient. There is no
setting needs to be fine-tuned.
VRAMDIR maps directories into RAM, while RAM-disks create new
drives. With VRAMDIR, it is easy to map existing directories,
e.g., TEMP directories, into RAM. There is no new drive letter
to worry about. Existing settings for the system and
applications do not need to be changed to point to the new
drive letter. VRAMDIR is very easy to set up, and the system
runs exactly like before, except that with VRAMDIR it will be
much faster.
===============================================
D. Advantages of VRAMDIR over Disk-Cache Utilities
===============================================
VRAMDIR is several times faster than disk-cache utilities.
VRAMDIR is not designed to replace disk-cache, but VRAMDIR
does something that disk-cache can not do. Disk cache cannot
replace VRAMDIR. They are used for different purposes.
Disk-cache keeps most recently accessed files in memory. You
do not have control of what to keep in the cache and what not.
VRAMDIR let you control what to be put in RAM. VRAMDIR is
designed to speed up temporary file access.
VRAMDIR is much faster than disk-cache in the best
circumstances. Many applications create temporary files on
hard-disks. With disk-cache, when a temporary file is created,
it will stay in memory for a short while. Then within, e.g., 1
second, disk cache will write the file out to hard-disks,
which is very slow. With VRAMDIR, files can stay in memory
much longer. A temporary file may stay in memory during its
entire existence, from the point it is created, to the point
it is deleted. Hard-disks may never need to be accessed in
these temporary file o