Using RAM Drives

A reader has asked how to create a RAM Drive.

You may well ask, What is a RAM Drive and why does anyone need one?

A RAM Drive is just like any Disk Drive only it uses a portion of the computer's memory as its foundation. Windows assigns a Drive letter, and then allows you to use that memory. You can copy programs and files to the RAM drive.

The advantage of a RAM Drive is that it's as fast as your memory. You can copy Hard Disk intensive programs, such as Data Bases to the RAM drive to improve their performance. You can use a RAM drive to store temporary files. When working with some graphics programs storing the graphics image files on a RAM drive may improve their performance. Although this is interesting application it is less popular these days with advent of faster Hard Drives.

There are of course disadvantages with a RAM drive. It uses some of your computers memory but with the low cost of memory today this is not as important as it was a while ago. It is only a temporary Drive. Like all RAM in the computer, when you power off the contents disappear including anything that was in the RAM drive. If you create or modify anything on the RAM drive, you must copy it back to the Hard Drive before you turn off the computer.

You can only use Windows 95 & 98 to create a RAM drive with the RAMDRIVE.SYS memory device driver. Because there is no Real Mode DOS in Windows ME, NT4 and all later Operating Systems you will need a special device driver not supplied by Microsoft but available from a number of sites on the Internet.

The RAMDRIVE.SYS driver is loaded in your CONFIG.SYS file with the following syntax.

DEVICE=PATH\RAMDRIVE.SYS SIZE SECTOR ENTRIES [/E|/A]

Path is the location of RAMDRIVE.SYS

Size is the size of the RAM Drive. Values range from 4 for a 4KB to 32767 for a 32MB RAM Drive. A default of a 64KB RAM Drive is created if not specified.

Sector is the sector size of the RAM drive. Values for sector can be 128, 256, or 512. If no sector is specified, a value of 512 is used.

Entries indicates the number of root entries on the RAM drive. Values range from 2 to 1024, 64 used if you don't specify.

E or A specifies whether to put the RAM drive in extended or expanded memory. With Windows 95 or later, specify /E. If not specified the RAM drive is built in conventional memory which is an undesired result.

When Windows creates the RAM Drive the Drive's icon (an Integrated Circuit icon) appears in My Computer. The RAM Drive is assigned a Drive letter one higher than the highest logical Hard Drive. An unfortunate side effect is that your CD-ROM Drive will now be moved one letter higher. It is also possible to have multiple RAM Drives by including additional RAMDRIVE.SYS entries in your CONFIG.SYS

As an example The following command in CONFIG.SYS creates an 8MB RAM drive in Extended memory. NOTE: If you use the /E switch you must load the extended memory manager HIMEM.SYS in your CONFIG.SYS before you load RAMDRIVE.SYS

DEVICE=C:\WINDOWS\HIMEM.SYS
DEVICE=C:\WINDOWS\RAMDRIVE.SYS 8192 /E

When the Computer is started DOS will assign 8192K of extended memory to the RAM Drive and display the message on the screen.

Microsoft RAMDrive version 3.06 virtual disk D:
Disk size: 8192k
Sector size: 512 bytes
Allocation unit: 8 sectors
Directory entries: 64

That's all there is to it. Change the value within the range 4 to 32767 to suit your requirements. Please note however that the Microsoft Knowledge base details potential problems for RAM Drives larger than 15MB.

A RAM drive larger than 15 MB is allocated all the available extended memory below physical address 16 MB. To start Windows 95 on most computers, some memory below 16 MB is necessary for DMA buffers. If all the memory below 16 MB is allocated to the RAM drive, Windows 95 cannot start.

Copy your database file(s) or perhaps set Internet Explorer to use this Drive for its temporary files. Users editing some graphics files may also find this an advantage. Please however make sure if you amend your database or anything else you locate on this Drive you copy it back to your Hard Drive before you shut down the Computer. To practise safe Computing you should copy back regularly to your Hard Drive particularly if feel you may experience any system lockups or other need to re-boot.

The RAM Drive represents an interesting concept which is sure to stimulate some readers into testing its operation.