China DOS Union

What does the smartdrv command mean?

Disk buffer memory can be used to pre-read the content on the disk into the memory. When these contents are needed, they can be read directly from the memory instead of reading from the disk, which speeds up the reading speed. In addition, there is write buffer, that is, the content to be written to the disk is first placed in the memory and then written to the disk集中ly, avoiding multiple writes to the disk, which can improve the efficiency of the system.

Why put the content of the disk into the memory?

Because the reading and writing speed of the memory is much higher than that of the disk.

But how does he know which contents on the disk should be read into memory?????? If what is read in is not what I want to use, isn't that a waste of memory for nothing?

Here are some algorithms involved, and I don't understand them either. But some are easy to understand. For example, file A is placed on 10 clusters (I don't know how to pronounce "簇" exactly; I can't type it out), and file B is placed on 8 clusters. The positions of these two files on the disk are adjacent. We first open A and then open B. If the system reads by itself, it will read A first, and only when we are about to open B will it read B. But smartdrv will load both A and B into memory. In this way, the speed of opening A may not be much faster, but the speed of opening B will be much faster.

You can do an experiment:

Boot with a DOS boot disk, then type the following commands:

cd\

Press Enter

dir/s

Press Enter

At this time, the system will list all non-hidden files in this directory. Calculate the time required;

Then run smartdrv, type the above command:

cd\

Press Enter

dir/s

Press Enter

Calculate the time. Is it much faster than when smartdrv is not run?

How to load smartdrv in a DOS boot disk. It seems that when I installed WIN2000 directly from the hard disk, the speed was slower than a snail, but it was faster with the CD-ROM.

This is because the startup CD of WIN2000 uses a similar buffering technology. A few years ago, I entered the CD to install the WIN2000 beta version (reported by China Computer) under DOS, and it took a total of more than 7 hours to install.

SMARTDRV.EXE can be obtained from the installation files of WIN98/95. Put it into the boot disk, and you can load it with the SMARTDRV command. It can also be written into autoexec.bat.