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DEC TOPS-10 for the PDP-10

Having never used TOPS-10 in real life, it seemed like a good idea to get familiar with it first, using another emulator. Thankfully, The Digital Antiquarian created “TOPS-10 in a Box”, everything you need to run TOPS-10 on a virtual PDP-10.

From README.txt (in the “TOPS-10 in a Box” zip file):


1. Bring up a command prompt in the PDP-10 In a Box directory using whatever technique is normal for your platform.

2. Enter "pdp10 tops10.cfg".

3. At the "BOOT>" prompt, just press enter.

4. At the "Why reload:" prompt, enter "NEW".

5. At the "Date:" prompt, just press enter to accept your host computer's current date.
   If you wish, you may enter another date in the format "MM-DD-YYYY".

6. At the "Time:" prompt, just press enter to accept your host computer's current time.
   If you wish, you may enter another time in the format "HHMMSS".

7. At the "Startup option:" prompt, enter "GO".

8. After a moment, the system will place you in the system operator's console (denoted by the "OPR>" prompt).
   To work with programs and files like a normal user, just type "EXIT" here.

Unfortunately, my first attempt hung after step #3, which I resolved by downgrading from SIMH V4.0 to the older SIMH V3.9. Here’s the resulting output:

PDP-10 simulator V3.9-0
Listening on port 2020 (socket 5)
Modem control activated
Auto disconnect activated
Logging to file "tops10.log"
BOOT V4(76)

[Loading from DSKB:SYSTEM.EXE[1,4]]

KS10 07-Oct-88
Why reload: NEW
Startup option: GO
[Rebuilding the system search list from the HOM blocks]

[Rebuilding the active swapping list from the HOM blocks]

[Rebuilding the system dump list from the HOM blocks]

KS10 09:09:41 CTY system 4097
Connected to Node CENTRA(0) Line # 42
.LOGIN 1,2

[CCPWFD Waiting for file daemon to start]
%%TTY STOMPER - Starting
 9:09:51          -- Message from the Accounting System --
				Account validation is not required

 9:09:52        -- Begin auto take file --
				File: SYS:SYSTEM.CMD[1,4]

 9:09:52        -- End auto take file --
				17 lines processed


At this point, I stopped, because now that I knew the pdp10 binary from SIMH V3.9 worked on my system (macOS), I wanted to create an Xcode project to build just that binary, and make it easier for me to modify and debug that binary.

I had already run make to build the official SimH pdp10 binary, so in order to isolate all the commands required to build just pdp10, I re-ran make with -B to unconditionally remake all targets and -n to print the commands that would be executed with executing them, and then isolated the PDP10-specific command(s) with grep:

make -Bn | grep pdp10

I was pleasantly surprised to see that there was only one (albeit rather lengthy) command:

gcc -std=c99 -U__STRICT_ANSI__  -O2 -finline-functions -flto -fwhole-program -I . -D_GNU_SOURCE -DUSE_READER_THREAD \
-DHAVE_DLOPEN=dylib  PDP10/pdp10_fe.c PDP11/pdp11_dz.c PDP10/pdp10_cpu.c PDP10/pdp10_ksio.c PDP10/pdp10_lp20.c \
PDP10/pdp10_mdfp.c PDP10/pdp10_pag.c PDP10/pdp10_rp.c PDP10/pdp10_sys.c PDP10/pdp10_tim.c PDP10/pdp10_tu.c \
PDP10/pdp10_xtnd.c PDP11/pdp11_pt.c PDP11/pdp11_ry.c PDP11/pdp11_cr.c scp.c sim_console.c sim_fio.c sim_timer.c \
sim_sock.c sim_tmxr.c sim_ether.c sim_tape.c -DVM_PDP10 -DUSE_INT64 -I PDP10 -I PDP11 -o BIN/pdp10 -lm -lpthread \
-ldl   -flto -fwhole-program

It was time to build the Xcode project.