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A project log for Novasaur CP/M TTL Retrocomputer

Retrocomputer built from TTL logic running CP/M with no CPU or ALU

alastair-hewittAlastair Hewitt 07/24/2023 at 03:040 Comments

It's done! As in the software is at version 1.0 and ready to ship.

             _
            /o)
   _/\/\/\_//
 _/NOVASAUR/
/_/{_}~~{_}

Novasaur 64k CP/M vers 2.2
Copyright 1979 (c) by Digital Research

a>b:uptime

System uptime: 0 days, 03:18:38

           CPU Load Average (last 4 mins)
     0      0.5     1.0     1.5     2.0     2.5
     +-------+-------+-------+-------+-------+
0.05 |              .
0.05 |              .
0.05 |              .
0.06 |=            .
0.67 |===========.
1.02 |==========.=====
1.03 |==========.=====
0.30 |====         .
0.07 |=             .
0.24 |===            .
0.15 |==             .
0.29 |====          .
0.05 |              .
0.05 |              .
0.05 |              .
     +-------+-------+-------+-------+-------+
     0%      5%     10%     15%     20%     25%
           CPU Idle Cycle % (dotted line)

The last pieces of the puzzle have been added to the B: drive highlighted below.

B: ASM      COM : BASIC    COM : CPM      SYS : DDT      COM
B: DUMP     COM : ED       COM : FORMAT   COM : LOAD     COM
B: PIP      COM : STAT     COM : SUBMIT   COM : UPTIME   COM
B: XFER     COM : XSUB     COM

 These are three small (1k) utility programs as follows:

FORMAT

Used to format any CP/M drive installed on the Novasaur. Currently this would only apply to drive A:

FORMAT drive: [/Y] [/B]
  /Y    Confirm without further prompt.
  /B    Bleach the file system (set all bytes to ctrl-Z).

UPTIME

As shown above. This returns the time elapsed since the last cold boot and a chart showing the load average and CPU idle percentage over the last four minutes. 

XFER

Used to send and receive binary files over the serial connection. This was originally going to be XMODEM, but this was changed to a basic file transfer utility. The USB FTDI connection is reliable and the transfer can be completed with a simple send or capture command from the host.

XFER <drive:filename.ext> {/R or /S}
  /R    Receive file over serial.
  /S    Send file over serial.

The XFER program detects if it running on the TTY and will respond appropriately. File capture from CRT will ask for a keyboard confirmation to start the file transfer. From TTY an extended timeout is used to allow time to control file capture without confirmation.

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