China DOS Union

With the development of the times, the memory of computers has become larger and larger, developing from the original 1M, 2M, 4M, etc. to the current 128M, 256M, 512M, or even larger. Therefore, it is very important to reasonably allocate and use memory to avoid unnecessary waste. Moreover, compared with general external storage devices, such as the disks (including hard disks, optical disks, etc.) that everyone usually uses, memory has many advantages. For example, the speed of memory is very fast, usually dozens of times faster than the latter; the capacity of disks is limited, especially floppy disks. The size of a single floppy disk is generally only about 1.44M, so the required programs are often not placed in the boot disk. Therefore, if memory can be used as a disk device to store files and data, it will undoubtedly greatly improve the operation speed, efficiency, and convenience, and can make the memory play its maximum utility, that is, effectively use the memory.

For this reason, people have developed many memory virtual disk programs, such as VDISK.SYS and RAMDRIVE.SYS that come with DOS. However, these programs have some drawbacks. For example, they need to be loaded in the CONFIG.SYS file and cannot be directly loaded on the DOS command line; once loaded, the size of the memory disk cannot be adjusted or deleted; the memory disk has a capacity limit, usually not exceeding 64M; and they themselves occupy more conventional memory. Now someone has finally developed a memory virtual disk program that solves all the above problems, which is the XMSDSK introduced below (available for download in "Disk Tools".

XMSDSK is a relatively new program and is quite powerful, practical, and stable. It is a part of the Furd memory toolkit, which means it creates a disk using XMS memory. Therefore, it must be used when there is XMS memory. Usually, as long as the DOS-built-in HIMEM.SYS program is loaded (if it is MS-DOS, it is best to use version 7.10 or above to make HIMEM.SYS support XMS memory above 64M), then it can be used casually. There are too many benefits of XMSDSK. For example, in addition to being able to be loaded in CONFIG.SYS, it can also dynamically adjust the size of the memory disk or disassemble it infinitely in the command line mode. It occupies very little memory, only a few hundred bytes of low-end memory, and can be automatically loaded into UMB (upper memory block) without using the LH command. It supports extremely large memory (currently up to 2G). Therefore, for example, if we have 512M of memory, we can even virtualize all XMS memory into a disk. If it is used in a boot disk, it can add a lot to this boot disk. It also has a very useful use. Because some software, such as some game software (such as "Chinese Paladin", can only run in memory below 32M. At this time, XMSDSK can be used to install a memory disk to make the free XMS memory less than 32M, so that those software can run normally. The most important thing is that it is very simple to use. The actual usage method will be introduced below. The usage syntax of XMSDSK is as follows:

XMSDSK

Among them, the memory disk size is expressed in KB. For example, 4 means 4K, 1024 means 1024K = 1M, etc. If not specified, a 0K memory disk will be created. The drive indicates the drive letter of the memory disk to be specified. If not, it will automatically use the next drive letter. For example, if there are only drives A, B, C, and D currently, the memory disk will be automatically loaded to drive E. The options are as follows:

/? : View command line help;
/Y : When performing an operation, no confirmation is required, that is, default to "Yes";
/U : Disassemble the memory disk and exit the memory;
/T : Locate the memory disk at the top of XMS memory;
/C : Specify the cluster size of the sectors in the memory disk.

And usually only the /Y and /U options are used.

When running XMSDSK without any parameters and options, that is, directly entering the XMSDSK command, if XMSDSK is currently loaded, it will prompt you whether to load it; otherwise, it will automatically display the status information of the loaded memory disk, such as the size of the memory disk.

Now let's give an example of using XMSDSK. For example, now I want to create a 5M memory disk, then adjust it to 10M, and finally delete this memory disk to release the drive letter and the used memory, and no confirmation operation is required when installing, adjusting, and deleting. Then the following commands can be entered in sequence on the DOS command line:

1: XMSDSK 5120 /Y (Create a 5M memory disk)
2: XMSDSK 10240 /Y (Adjust the size of the already created 5M memory disk to 10M)
3: XMSDSK /U /Y (Delete the loaded memory disk)

Everyone, isn't it very convenient?

In conclusion, XMSDSK is currently the best and most powerful tool for virtualizing disks using XMS memory under DOS. It is the best substitute for other similar software such as RAMDRIVE.SYS. Moreover, in addition to XMSDSK, there is EMSDSK corresponding to it developed by the same author, which is a tool for virtualizing disks using EMS memory. The specific usage can be said to be exactly the same as the above XMSDSK, and it will not be introduced in detail here.

After reading this instruction, I have some ideas, but I still feel not very proficient in using it. If I want to make a bootable img, its main function is to be able to automatically create a virtual disk with a capacity of 10M after successful booting, define its drive letter as Z drive, and then extract the three cab files in my img, namely abc.cab, ee.cab, dve.cab, into the virtual disk, so that we can use the files in the img without the boot disk. How to do this? Can you make an example for me to see? Please give me some advice. I am a novice and really want to learn something from you. I think I will use the above tool to create a virtual disk.

Try this:
XMSDSK 10240 Z: /Y
EXTRACT /L Z: *.CAB

After reading this explanation, I suddenly saw the light! I am determined to stop using RAMDRIVE.SYS. But there is still a small problem that I don't understand: In the text, "Usually, as long as you load the HIMEM.SYS program that comes with DOS... you can use it freely." I often see HIMEM.sys and EMM386.exe in the DOS boot disks. I remember that the latter is used to manage upper memory. I want to ask, when using XMXDSK, can I only load HIMEM.sys without loading EMM386.exe? That is, does XMXDSK have the function of EMM386.exe? I also heard that if both are loaded, it will limit memory (the statement is very vague). So I tried to load both. If I don't load EMM386.exe, it can all be used. I don't know if there is a difference. Please give me some advice!

In addition, I am not very clear about the terms low memory, high memory, extended memory, and expanded memory. If you are willing, please give me some advice!

You can use xmsdsk without loading emm386. xmsdsk has a sibling called emsdsk, which requires emm386.

楼主啊，I entered your website, but I can't download. It requires a username and password. There's no place to register. Urgent, urgent, urgent.

The boss is indeed the boss, I admire you!

This thing is very useful.

http://wcarchive.cdrom.com/pub/simtelnet/msdos/ramdisk/furd19_i.zip

Here you can download, both software are available

Really impressive~

Really impressive~