CompuServe Messages

Capture Files

    04-Mar-95 10:55:22
Sb: #3417-Capture Files
Fm: Vincent Chen 101400,1477
To: Bill Metzger 72172,3015
BM>> The problem is in the DOS file system, and potentially in how the capture program does I/O. If it's doing I/O with 512 byte blocks, it'll be slow. It should be using LARGE block sizes and double buffering. Blocks of 64 KB to 1 MB come to mind. Double buffering allows you to write a block while filling the next. I don't know if DOS/Windows will permit this type of behavior. DOS/Windows uses clusters of logical sectors and the block size get bigger as your partition size gets bigger. The disk drive buffer and its physical sector size is not a problem here. Yes, DOS will always use 512 bytes buffer to read/write data/directory, therefore, reduce the DOS buffer size (default 20) will speed up things. You can do it by adding a line like BUFFERS=3 at your CONFIG.SYS (it can't be set to 0 because DOS will hang). Also put a line, DEVICE=SMARTDRV.EXE /DOUBLE_BUFFER, at your CONFIG.SYS will allow SCSI adapter/drive to perform double buffering without lossing data due to the delayed disk cache flushing. –Vince Ulead Systems, Inc.