CONFIG.SYS

This is a configuration file for DOS systems which is used for loading devices into memory, setting operating variables and other configuration purposes.

CONFIGuration SYStem commands are needed to define certain hardware parameters. For example, if your system uses special size disk drives, extra printers, extra modems, extra input devices (joysticks, mouse), RAM disks, etc.

EX: CONFIG.sys

       FILES = 20
       BUFFERS = 15

In this example, FILES = 20 means that DOS will allow up to 20 files opened simultaneously. If this line were not present in CONFIG.SYS, DOS would only allow up to 7 files. Do we need up to 20? Certain programs (dBASE, Accounting, etc) state early in their manuals that this parameter needs to be set at 20 for the software to operate correctly.

The BUFFERS = 15 defines a staging area within RAM for portions of files that are not on the screen yet. For example, in an Accounting program if you told the computer to bring up the last 10 invoices entered, it would display these 10 invoices. However, unknown to you it actually took the last 30 invoices in anticipation that you would want to see them right away also. The extra 20 that the system brought into RAM are sitting within the BUFFERS. DOS allows this and does this as a way to speed up the system. Items that are sitting in RAM can be accessed seemingly instantly versus items that must be sought from a disk.

If not told, DOS automatically sets BUFFERS to 3. If BUFFERS are so useful, why not set them to their maximum of 99? The reason is that DOS is guessing which information you will need next. If it guesses wrong - for example the next invoice you wish to look at is 1500 ago, it must first check all the BUFFERS before realizing that it will have to go to the disk to retrieve the needed information. It actually slows the process down in this case. Most purchased software will note if this command is needed and what to set it to. BUFFERS = 15 is a common level to operate at.


See Also