RSX utility for converting Logical Block order virtual RX50 disks to Track, Sector order.

   Several posts back. I posted a utility, TSTOLBN, that converts RX50 disk images that are in the same layout as a physical RX50 diskette (I call that Track, Sector or TS  order - it  has the blocks in a track  interleaved every other block, and the track  starting sector  is skewed by two sectors/each track, plus the last track is at the first physical track on the disk) , into just a string of blocks, in numerical order - the format used by RSX and VMS virtual disks, and SIMH disks (I call that Logical Block order, LBN). 

  That does the business for all of my needs - I use RX50 images as files on P/OS, RSX, VMS and SIMH, and they all need LBN format. Additionally, if you have an LBN order virtual disk, you can read and write it directly ro a real RX50 diskette, and the MSCP/Pro Controller will take care of converting it to/from the physical Track Sector format on the disk for you. But I've been noticing of late that people are needing RX50 images that they can use in assorted external disk emulating gizmos - and they all required the same format as a physical RX50 uses - TS order.

  Several folks have written converters in C and Python to convert LBN to TS order. But I prefer to work in the DEC environment as much as possible, so I needed a tool to do this conversion, that runs purely in the RSX and P/OS environment, no Windows/Linux/Python/C compiler required.

  So I took a little time and, using the previous converter (TSTOLBN, Track Sector To LBN) as a base, created a utility called LBNTOTS (Logical Block To Track Sector).

  Really, it's almost the same program - just had to make a few changes to the interleave and sector translation arrays, and the funny first track/last track logic. And I cleaned it up a little in general. 

  Here's the source code...

lbntots.mac

To make...
 >mac lbntots=lbntots
 >tkb
 TKB>lbntots=lbntots
 TKB>/
 Enter Options:
 TASK=...LTT                   ;stands for LBN To TS
 LIBR=FCSRES:RO       ;this is optional - saves memory on a busy system
 //
>

 To use...
 >run lbntots
 LTT>outfile=infile

 or install it and use direct from the command line

 >ins lbntots
 >LTT outfile=infile

 Outfile extension defaults to .dsk, infile extension to .dsk