Emulated Hard Disk

A single hard disk is emulated through a disk image file. An image file can be as large as 71 MB. If one of the following file sizes is used, the emulator will auto-detect the emulated disk geometry (heads, cylinders, sectors). Filesize Heads Cylinders Sectors Disk type -------- ----- --------- ------- --------- 5,013,504 4 153 16 RD50 5M 5,326,848 4 153 17 RD50 5M 10,027,008 4 306 16 RD51 10M 10,653,696 4 306 17 RD51 10M 20,152,320 4 615 16 RD31 21M 21,411,840 4 615 17 RD31 21M 33,554,432 8 512 16 RD52 36M 35,651,584 8 512 17 RD52 36M 40,304,640 6 820 16 RD32 43M 42,823,680 6 820 17 RD32 43M 67,108,864 8 1024 16 RD53 71M 71,303,168 8 1024 17 RD53 71M Other sizes may be used, but the disk geometry will have to be specified manually. The sector size is 512 bytes, so the following equation applies: file_size = heads * cylinders * sectors * 512 Set the path to the directory that contains the hard disk image file with the "rd_dir" variable in the configuration file. Specify the disk image file to be used with the "rd0" variable. For example, to use the provided Venix 2.0 disk image, from the current directory, put the following in the configuration file: rd_dir = . rd0 = venix2.rd As an example, to create a custom 6,144,000 byte image by the name of "image.rd," perform the following from a Linux shell prompt: dd if=/dev/zero of=image.rd bs=6144000 count=1 Then, to attach it to the emulator, as a disk with 6 heads, 200 cylinders and 10 sectors, specify the following in the configuration file: rd0 = image.rd, 6, 200, 10 Additionally, since this newly-created image is blank, it would make sense to specify a bootable floppy image to boot from (see the "Emulated Floppy Drives" section). If no configuration file is present, or if no hard disk image is specified, the emulator will attempt to use a file by the name of "pos32.rd" in the current directory. All real hard drives used by the Pro seem to have 17 sectors. However, neither P/OS nor Venix seems to access the 17th sector. To save disk space, the 16-sector formats specified in the table may be used.