These files were downloaded from Bitsavers on 05.04.2020, as raw disk images with ".P75" filename suffixes.

In April 2020, I used ImageDisk to convert them to .IMD images.

Included in this directory is a file called CONVERT.BAT that was used to convert the images from .P75 to .IMD format.

The background to these images is described on http://www.willsworks.net/decmicro.

Here is the most relevant paragraph from that webpage:

When I published the Technical Reference scans I included copies of my system software disks which are available at BitSavers. Caution, these are raw physical disk images obtained on a faster machine which was capable of track at once reads of the media. To recover the data you must deal with the sector interleave the VT-180 disk controller imposed. The VT180DSK.LST is a list of the disks by DEC part # with a very brief description. If memory serves they were all bootable, the two key disks VT18DIAG, the diagnostics disk, and VT180CPM, the CPM 2.2 boot disk, definately were bootable. I believe everything in this list with a 'BJ-" part number came in the original distribution. SELECT was the distributed editor, SUPERSPL was the associated spell checker, and SINSTTCH was a tutorial for Select. For programming I had the distributed MBASIC, Microsoft's Mbasic, and TPASCAL a version of Turbo Pascal I purchased separately. MULTIPLN is the distributed spread sheet program. VTKERMIT contains a compatible version of Kermit from Columbia University and another serial communications program, POLYGON.

Malcolm Macleod
www.avitech.com.au
7 April 2020