Jeff’s page of AT&T 3B2 stuff


page index


In the late 80s, “The Right Choice” was AT&T’s advertising slogan for all divisions.
I lament not getting the internal copy of the full symphonic version of the AT&T jingle (which played while we were waiting for for internal teleconference meetings), or the strange training video showing the founding fathers effectively using conference calling, or internal commercials such as “The Software Blues” (for an internal consulting group for salesmen to get the custom software they needed to sell stuff that didn't-exist-yet) or “The Road To Success” (a Unix rah-rah video singing the tale of the trucker hauling 3b2s and modems to country/western music, showing some of my AT&T Summit Facility co-workers)

Bell Labs was the crown jewel of the AT&T empire.
Dr. Narain Gehani (now dean of NJIT's Computer Science Department) laments the loss of Bell Labs' pure research in his book: Bell Labs: Life in the Crown Jewel. Many former Bell Labs researchers and staff are now professors and staff at NJIT, MIT and other research colleges.
A cute promotional item from AT&T: a blank notebook.
A flyer for the WE 32000 chipset



I consulted to AT&T Information Systems for many years. The 3B2 is the desktop/minitower version of the WE32000 CPU based systems. The 3B* series has a noble lineage starting with the 3B20 duplex system (designed to run the phone switches with a downtime of only minutes per year).

I had a 3B2/400 on my desk since it was the porting base for Unix SVR4.0.
I was a software developer for SVVS: System V Verification Suite and later the file system commands for SVR4.0.
I got to know the machine really well, inside and out thanks to the appropriate manuals.

The “documentation roadmap” listed all the manuals related to a machine or product. There was a distinction between reference manuals and user guides. I think manuals are the concise and terse “man pages” that are great as reminders for options or details but not for learning the concepts, whereas guides are more like essays or textbooks giving “best practices”.

Since the manuals were printed and distributed only by the AT&T CIC (Customer Information Center), they are identified by their 6 digit “select code” and name (no International Standard Book Number ISBN). Sadly, none seem to be available anymore, and even the software repositories (such as the Unix Toolchest or TOAD) are gone (along with all the fun BLIT games such as GEBACA and graphical tools such as CIP).

Manuals essential for 3B2 computer maintenance

AT&T 3B2 Computer Maintenance Reference Manual
305-395 (large brick colored looseleaf in slip case)
This details how to initialize or clone disks, test feature cards and the motherboard using the firmware and the enclosed 5.25” floppy disk of “3B2 Computer Maintenance Utilities” called “idtools ” (formerly known as “devtools”).

AT&T 3B2 Computer Off-Line Diagnostic Manual
305-494 (large brick colored looseleaf in slip case)
Everything you wanted to know about the inner details of the diagnostics.


Manuals essential for 3B2 kernel & operating system

Many of the 3B2 firmware features were NOT documented in the 3B2's man pages or manuals or user references, but WERE found in other WE32000 based products since the firmware, Unix boot procedure and device driver linkage were all ported from the 3B2.

AT&T 3B2 Computer Debug Monitor Guide
305-442
I'm unsure if this was only internal to AT&T. The “DEMON” roms allowed debugging the in-core kernel (live or post-mortem) with a firmware debugger specific to that Unix kernel version.

Unix System V/VME OEM Porting Manual
307-780
This manual explains the deep inner details of the 3B2 boot process (firmware, lboot, mkunix) and documents things not seen anywhere else, such as:
lboot prompts you with “Enter path name:”
enter “magic mode”
lboot replies “POOF!” “A hollow voice says (directory)”

Instead of load-and-run, it loads the kernel
and then breakpoints before entering with the message
“You are standing inside of a large unexecuted /boot/KERNEL
The only exit you see is at 0x108000”

AT&T 3B2/3B5/3B15 Computers Assembly Language Programming Manual
305-000
For those times “C” is not enough.

WE 32100 Microprocessor Information Manual
305-730
All the microprocessor's instructions, registers and functional units.

WE 321EB Microprocessor Evaluation Board User Manual
451-019
This explains the hardware of the WE 32000 based single board computer, particularly how it's derived from the 3B2 firmware. I never used one but it looks cute, with 2: 4 character 16 segment smart displays in the corner and a firmware monitor chock-full-o-commands for software development & debugging, as well as a thorough System Self Test.

3B2/Unix Device Drivers & hardware

AT&T 3B2 and 3B5 Computer Driver Design Guide
305-495 (grey and red looseleaf)
I'm unsure if this was used by the Maurice Bach internal courses for the Unix kernel (the textbook was mostly a listing of the source code).
Perhaps due to rivalry or NIH (Not Invented Here), there was never any reference to The Lions Book: Lions' Commentary on UNIX 6th Edition, with Source Code by John Lions (1976) which contains the complete source code of the 6th Edition Unix kernel plus a commentary. For many years, the Lions Book was the only Unix kernel documentation available outside Bell Labs.

Unix System V, Release 3 Block and Character Interface (BCI) Driver Reference Manual
307-192 (brick red spiral bound)

AT&T 3B2 Computer Feature Card Interface Design Manual
305-492
How to design the cards for the 3B2 bus: physical, electrical and firmware.

These books together describe the hardware, firmware and operating system interfaces for writing device drivers.

Unix System V/VME Driver Design Guide
307-771
A great companion to the AT&T 3B2 Computer Feature Card Interface Design Manual because it describes ALL the firmware, hardware linkages, kernel and driver interfaces. Most 3B2 manuals assumed familiarity with AT&T products and the Unix environment whereas the VME systems were targeted to hardware developers working outside of AT&T without all the AT&T internal resources (such as local gurus to ask for help).

See also: brochure & press release for the 32000 based AT&T VME SBC


Other 3B2 resources



The 3b2 was usually used via the 5620 graphic terminal AT&T/Teletype 5620 Dot Mapped Display Terminal
The 5620 was the first commercial version of Rob Pike's BLIT terminal. The original BLIT design used a common Motorola 68000 microprocessor. Since Western Electric, an AT&T subsidiary, was in the microprocessor business, the 5620 used a Western Electric WE32000 microprocessor instead. Later models, the 630 and 730, reverted to the 68000.
AT&T 5620 (and Related Terminals) Frequently Asked Questions

Re: Plan 9, GNOT, 5620 terminals


Other things

The 8 pin modular RS232/serial connectors are:

motherboardEPORTS cardDB25 to terminalDB25 to modem
1 prot ground1 prot gnd11
2 N/C2 CTS (IN)45
3 TXD3 TXD (OUT)32
4 DTR4 DTR (OUT)820
5 RXD5 RXD (IN)23
6 DCD6 DCD (IN)208
7 signal gnd7 signal gnd77
8 N/C8 RTS (OUT)54

I think the terminal pinout is DCE, the modem pinout DTE.
Flat un-twisted silver “satin cable” is fine since it's low speed compared to ethernet (which requires twisted pair such as CAT-5).