Using the Filename Parameters of DOS CHKDSK Frank Bolton New York Personal Computer, Inc. Many people do not fully utilize the capabilities of the DOS CHKDSK command. The Commands section of your DOS manual gives three parameters that you can enter with the CHKDSK command in addition to the drive specifier: [filename][/F][/V]. We will look at one of them in this article: filename. The CHKDSK command examines a disk in the drive you specify (CHKDSK B: for instance) and tells you how much memory remains on the disk (and also reports on how much memory is available in RAM). It also conveys information about problems that may be occurring on the disk, such as invalid clusters (which results in a truncated file) or other problems which would impede data recovery. If you issue the command CHKDSK followed by a file name, it will tell you if the file you are checking is stored in contiguous blocks on your disk. If it isn't, CHKDSK will tell you in how many different places on the disk the file is stored. If you wish to see how many files are stored non-contiguously, enter the following command CHKDSK [x:]*.* When you store data on a disk, it is stored in the first available space. This means that when you erase files, there will be a "hole" or a series of "holes" available where the drive will write the next file you store. For example, if you erase a 4KB file and then store a 6KB file, the first 4K of the new file will be stored where the old file was, and the remaining 2KB will be stored in the next available space. You would have a file stored in at least two different places on your disk, or stored non-contiguously. If all of your files are thus fragmented, not only are your disks and disk drive heads getting undo wear and tear, but you increase the time your disk drive takes in retrieving your data. You also run a greater risk of scrambling your file allocation table, rendering your data irretrievable. If you listen carefully to your disk drives, you will hear a difference when it is retrieving data from disks where the files have become fragmented. If your file is fragmented over the whole disk, you will notice a lag in retrieval time for even small files. Running the CHKDSK [x:]*.* command will tell you whether your disk has many fragmented files. When you wish to consolidate your data into contiguous blocks, use the DOS COPY command. Put your disk with the fragmented files into drive A and a newly formatted diskette into drive B and enter: COPY *.* B: Do not use the DISKCOPY command because that copies your data sector by sector, not file by file, leaving every bit of data in the same place on the new diskette as it was on the old diskette. On the other hand the COPY *.* command will copy each file individually onto the new diskette in contiguous blocks of data.