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 Getting it working. 
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Joined: Sun Mar 27, 2022 12:11 am
Posts: 41
For examples of DOS. Unix version 6 and in particular the book "A Commentary on the Sixth Edition UNIX Operating System by John Lions" is probably the best resource I've found for an early 70's OS.

Apart from that, C/PM has it's BIOS writing guide and the source itself is available but not very readable.


Sat Feb 03, 2024 9:18 pm

Joined: Mon Oct 07, 2019 2:41 am
Posts: 619
DockLazy wrote:
For examples of DOS. Unix version 6 and in particular the book "A Commentary on the Sixth Edition UNIX Operating System by John Lions" is probably the best resource I've found for an early 70's OS.

Apart from that, C/PM has it's BIOS writing guide and the source itself is available but not very readable.


Both systems have flaws. CP/M was designed for a 256 kb floppy and Unix 3 was designed for multi user with disk swapping.
DEC RT 11 (PDP 11) is more what I am looking for, but all have a tiny program/data space of 64kb. (32K words).

George III for the ICL 1900 really is good example of 60's operating system, as it had cards,paper tape,mag tape,and removable hard disks
and printers and video and hardcopy terminals that is of historical interest. I suspect it all ran in 32K words with swapping.

The evil mind thinks of running ICL emulator and porting BCPL to the EVIL computer.

I fixed a few more bugs, today but still have problems.


Sat Feb 03, 2024 10:43 pm

Joined: Mon Oct 07, 2019 2:41 am
Posts: 619
Well new MAX 232's are exploding left and right. I hand to use a junk box find, that works.
My skip opcode seemed flakey, so I replaced my HCT/ALS chips with 74LS parts that I found
looking for max 3232 chip, for less noise. Now my quick and dirty boot loader, works with out flying into LA-LA
land. I need to now add another 32K RAM card so I have 32K for user space,and 32K O/S space + 16K rom.
Ben.


Fri Feb 09, 2024 5:54 am

Joined: Sun Mar 27, 2022 12:11 am
Posts: 41
HCT are pretty bad for noise. They have low voltage swing of TTL but with high impedance CMOS inputs, makes for the worst of both worlds.


Fri Feb 09, 2024 6:27 am

Joined: Mon Oct 07, 2019 2:41 am
Posts: 619
Just in time, a better mother board. 2 oz copper and better switches.
I would love it to be base 8, but only Sexadecimal fits the PCB, for a 24 bit binary CPU.
"Alpine Computer 1"


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Sat Feb 10, 2024 9:51 pm

Joined: Mon Oct 07, 2019 2:41 am
Posts: 619
Code:
00000         
00000         /       HELLO WORLD PROGRAM
00000         /       ALPINE 1
00000         GETC    SET $FF8009
00000         PUTC    SET $FF800A 
00000         CRLF    SET $FF800B 
00000         
00000                 RIM
00300                 ORG     $300
00300  1C030A         LD  X # STR
00301  C8800B         JSR A # CRLF
00302         LOOP
00302  130000         LD  A X 0
00303  2C0001         ADD X #1
00304  710005         SNE A
00305  780308         JMP A # EXIT
00306  C8800A         JSR A # PUTC
00307  780302         JMP A # LOOP
00308         EXIT
00308  C8800B         JSR A # CRLF
00309  000002         HLT A
0030A         
0030A  000048
0030B         STR     DW 'H
0030B  000065
0030C                 DW 'e
0030C  00006C
0030D                 DW 'l
0030D  00006C
0030E                 DW 'l
0030E  00006F
0030F                 DW 'o
0030F  00002C
00310                 DW 44 / ,
00310  000020
00311                 DW 32 / SPACE
00311  000057
00312                 DW 'W
00312  00006F
00313                 DW 'o
00313  000072
00314                 DW 'r
00314  00006C
00315                 DW 'l
00315  000064
00316                 DW 'd
00316  000021
00317                 DW '!
00317  000000
00318                 DW 0
00318         
00000                 END



1st mile stone, working ABS loader. (Bootstrap)


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Sun Feb 11, 2024 11:15 pm

Joined: Wed Jan 09, 2013 6:54 pm
Posts: 1789
Well done!


Mon Feb 12, 2024 9:06 am

Joined: Mon Oct 07, 2019 2:41 am
Posts: 619
Now for the bug fix PCB's. More caps and better layout.
4 bit alu, using PAL's.


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Mon Feb 12, 2024 6:48 pm

Joined: Mon Oct 07, 2019 2:41 am
Posts: 619
and A revamped memory/Io card. IDE interface is 12 bits wide now. Acia has its own clock.


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Tue Feb 13, 2024 2:54 am

Joined: Mon Oct 07, 2019 2:41 am
Posts: 619
Fixed a few bugs, in the cross assembler with emited code.


Fri Feb 16, 2024 7:03 am

Joined: Mon Oct 07, 2019 2:41 am
Posts: 619
While waiting for the new PCBs I am drafting out a new control section using TTL logic and 28C16s as prom replaments.
Some decoding changed to permit better use of TTL logic. I saved 1 logic gate. Some parts had to be changed to 74Fxx
to meet timing, as the 28C16s are 70 ns slower than bipolar proms. 3 1024x8 proms are used in the design now,
and lots 74ls153s and 74ls161s and 74163s (No PALs here). Revised timing is .9 uS clock cycle, or 1.8 uS for a memory read.
Writes add 1 cycle more. I hope to have the PCB's in by the weekend.


Thu Feb 22, 2024 6:15 am

Joined: Mon Oct 07, 2019 2:41 am
Posts: 619
Now waiting for some last minute parts. I have a few ideas for a 20/10 bit cpu?
8 1/4 " x 5 1/4 inches for the alu card.


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Mon Feb 26, 2024 4:25 pm

Joined: Mon Oct 07, 2019 2:41 am
Posts: 619
Had a logic issue with the front panel switches on the new mother board.
Now working on the compact flash software.


Fri Mar 08, 2024 8:03 am

Joined: Mon Oct 07, 2019 2:41 am
Posts: 619
The compact flash seems to work. I have a paper tape bootstrap and now a disk bootstrap.
I read 1K blocks, of 12 bits, but pack that into 512 words. I read block 0 at 0x000300
and jump to it for my disk boot.
Right now I am using a fake IBM 2315 disk cartridge - 3 sectors of 512 (24 bit) words per track
using some sort of GCR ,3072 12 bit words. A PDP-8 gets 4096 12 bit words. The orginal IBM
format is 2560 8 bit words.
I am about the same state system wise I was in May 2023 using a FPGA, but here I have better chance
upgrading my I/O and memory.
24 bits is just ample to fit the order code, with 4 registers and two addessing modes and to have more than
a 32K (word) address space. I may use FAT style disk layout if I use the disk cartridge as floppy style system.
IBM 1130 style computer for now.
Ben.


Sat Mar 09, 2024 9:48 am

Joined: Mon Oct 07, 2019 2:41 am
Posts: 619
Bad news, I am stuck with 256 word sectors for the compact flash.
Good news, I have another 32K words of ram.


Sun Mar 10, 2024 7:45 am
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