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IBM 5110

From RetroTechCollection
Revision as of 21:47, 24 September 2026 by Josh (talk | contribs) (Fix refs so they render; PSU is a transistor switching regulator (five rails incl +8.5 V), not linear; processor is slot J2 not G2; IEEE bus verified from IBM logic sheet 445 (24-pin Y3, card K2); EBCDIC claim removed - the word appears nowhere in the 5110 MIM; add bring-up diagnostic card mapping)
IBM 5110 Computing System
IBM 5110 Computing System at the Ridai Museum of Modern Science, Tokyo
Specifications
DeveloperIBM General Systems Division; designed at IBM Rochester, Minnesota; project led by Bill Sydnes
ManufacturerIBM
TypeDesktop business computer
ReleasedJanuary 1978 (announced); first customer shipment 2 February 1978 to Punxsutawney Electric Repair
Discontinued31 March 1982 (Models 1 and 2); Model 3 (= IBM 5120) withdrawn 10 December 1982
CPUIBM PALM (Put All Logic in Microcode) — 16-bit board-level processor (same as IBM 5100). 1.9 MHz, 530 ns 2-byte cycle. 13 bipolar gate arrays
MemoryRWS (RAM) 16 / 32 / 48 / 64 KB in 16 KB increments. Executable ROS + Language ROS (APL / BASIC); sized for the larger EBCDIC character set support
StorageModel 1: 1 × DC300 1/4-inch cartridge tape drive built-in. Model 2: no internal tape; diskette only via external 5114. Model 3 (= 5120): 2 × 8-inch floppy drives built-in. External IBM 5114 Diskette Unit (1 or 2 × 8-inch floppy drives, 1.2 MB each, up to two 5114 units for 4 drives × 1.2 MB total)
DisplayIntegrated 5-inch CRT (same as 5100), 1024 characters (16 × 64) addressable
SoundNone
Dimensions~610 mm wide × ~440 mm deep × ~240 mm high (same shell as 5100)
Weight~25 kg
OS / FirmwareAPL and / or BASIC interpreter as operating environment. EBCDIC character set throughout (different from 5100's 5100-specific code). PALM microcode includes the same System/370 and System/3 instruction-subset emulators as the IBM 5100
PredecessorIBM 5100 (1975)
SuccessorIBM 5120 (1980, also designated 5110 Model 3)
Model no.5110

The IBM 5110 Computing System is a desktop business computer announced by IBM General Systems Division in January 1978 and first shipped on 2 February 1978 to Punxsutawney Electric Repair — whose vice-president Jeff Grube said "If you can type and use a hand-held calculator, you have all the skills necessary to operate a 5110."[1] Models 1 and 2 were withdrawn on 31 March 1982; Model 3 (= the IBM 5120) was withdrawn on 10 December 1982.[1]

The 5110 was designed at IBM Rochester, Minnesota; the project was led by Bill Sydnes in a reportedly 90-day concept-to-production effort. Sydnes later joined Bill Lowe's task force that produced the IBM PC (5150) — making the 5110 a direct ancestor in personnel as well as architecture.[2]

Relationship to the IBM 5100

The 5110 is the successor to the IBM 5100 Portable Computer, sharing:

  • Same PALM board-level processor.
  • Same 5-inch CRT housing and shell.
  • Same APL and BASIC language environments.

The 5110 adds:

  • A different internal character code. The 5100 uses a 5100-specific internal code (the code chart is in section 6 of its maintenance manual); 5110 data is not byte-compatible with it. The widely repeated claim that the 5110 "uses EBCDIC throughout" could not be confirmed: the word EBCDIC does not appear anywhere in the 5110 maintenance manual, and what the manual does document is a keyboard code-translation stage and a Katakana check jumper.[3] Treat the incompatibility as real and the name "EBCDIC" for it as unverified.
  • An IEEE bus on a 24-pin parallel I/O connector. IBM's logic manual labels it "IEEE Bus (bi-directional)" on sheet 445 and shows the ATTN, IFC and EOI lines of the IEEE-488 / GP-IB protocol, driven from the parallel I/O card in slot K2 through external connector Y3; pin 12 is the protective ground, bonded to the frame. IBM also supplies a parallel I/O wrap connector for testing the port without an instrument attached.[4] This is the 5110's most distinctive interface and it has no 5100 equivalent.
  • Asynchronous communications and serial I/O on device address 8, and a BSCA (binary synchronous) adapter on device address 6.[3]
  • External diskette support via the IBM 5114 Diskette Unit.

Models

IBM 5110 models
Model Storage Notes
Model 1 Built-in DC300 1/4-inch tape drive (204 KB / cartridge) + optional external 5114 Direct equivalent of the 5100 form factor
Model 2 No internal tape; diskette only via external 5114 Diskette-first configuration
Model 3 No internal tape; 2 × built-in 8-inch 1.2 MB floppy drives; 9-inch CRT; detached keyboard Marketed separately as the IBM 5120 from 1980

Architecture

The 5110 uses the same processor as the IBM 5100, on the same 15.1 MHz oscillator producing 66.2 ns clock pulses.[3] On the 5110 it sits in slot J2 — not G2 as on the 5100, where J2 is the display card. Get this the wrong way round and the bring-up halt codes point you at the wrong card.[3]

IBM's name for it is the processor or controller; the internal name PALM appears nowhere in the 5110 manual. Memory architecture matches the 5100:

  • Executable ROS — microcode + monitor in PALM's directly addressable 64 KB.
  • Language ROS — APL and / or BASIC interpreters in a separate ROS address space; PALM accesses it as a peripheral.
  • RWS (RAM) — 16, 32, 48 or 64 KB. Cards M2, M4, N2 and N4.[3]

The PALM microcode includes the same System/370 and System/3 instruction-subset emulators as the 5100, used to run the unmodified APLSV and System/3 BASIC interpreters in their original object code.

Form Factor

  • Same shell as the 5100, with a different cosmetic colour scheme.
  • Integrated 5-inch CRT — 1024 characters (16 lines × 64) addressable.
  • Integrated keyboard with APL, BASIC, or dual-language keytops (toggle on dual-language units).
  • Front-panel storage — DC300 cartridge tape (Model 1) or floppy port (Model 2 connects to external 5114).
  • Weight and dimensions match the 5100 — approximately 25 kg.

Storage

  • DC300 cartridge tape (Model 1 only) — 204 KB per cartridge, same drive as the IBM 5100.
  • IBM 5114 Diskette Unit (external) — 1 or 2 × 8-inch floppy drives; up to two 5114 units attachable to a Model 1 or Model 2, giving four drives × 1.2 MB = 4.8 MB total online (Model 3 limited to one external 5114).
  • Diskette formats — single-sided "Diskette 1" (~250 KB) vs Diskette 2D (double-sided double-density, 1.2 MB). The 5114 writes Diskette 2D format.
  • IBM 5106 Auxiliary Tape Unit — external second DC300 drive (Model 1 only).

I/O and Peripherals

  • IBM 5103 Printer — matrix printer carried over from the 5100.
  • IBM 5106 Auxiliary Tape Unit — external DC300 second drive (Model 1).
  • IBM 5114 Diskette Unit — defining peripheral of the 5110.
  • 5110 Async Communications Feature (SY31-0557) — start-stop over RS-232.
  • Parallel I/O (IEEE bus) — card K2, connector Y3, 24 pins.[4]
  • Communications Adapter — IBM 2741 terminal emulation for host connectivity.

Languages: APL and BASIC

The 5110 supports APL and BASIC, the same as the 5100. The language semantics are identical but the internal character coding is not, so 5100 data is not byte-compatible with 5110 data. APL is APLSV, retargeted from System/370; BASIC is the System/3 port. Which language a machine will come up in is set by a basic language jumper on the A1 board, and there is a separate Katakana check jumper — both are documented under Service Aids, and both have been found in the wrong position on machines that "won't boot the right language".[3]

Service Documents

Four of these are hosted on this wiki; the rest are at Bitsavers.

  • GA21-9300-0 — IBM 5110 General Information Manual, December 1977.
  • GH30-0232-1 — IBM 5110 / 5120 Computing Systems Bibliography, September 1980 — the master reference list.
  • SY31-0550-2 — IBM 5110 Computer Maintenance Information Manual (MIM), February 1979 — the CE service manual. Hosted here: IBM 5110 Maintenance Information Manual.[3]
  • SY31-0552-3 — IBM 5110 System Logic Manual, February 1979 — the fold-out logic sheets. Hosted here: IBM 5110 System Logic Manual.[4]
  • SY31-0553-2 — IBM 5110 System Maintenance Analysis Procedures (MAP), January 1979.
  • SY31-0551-1 — IBM 5114 Diskette Unit Maintenance, January 1979. Hosted here: IBM 5114 Diskette Unit Maintenance Information.
  • S131-0626-1 — IBM 5114 Diskette Unit Parts Catalog, September 1978. Hosted here: IBM 5114 Diskette Unit Parts Catalog.
  • SY31-0557-0 — IBM 5110 Async Communications, January 1978.
  • SA21-9301-0 / -9302-1 / -9303-0 — APL Introduction / Users Guide / Reference.
  • SA21-9306-0 / -9307-2 / -9308-2 — BASIC Introduction / Users Guide / Reference (April 1979 revisions are most complete).
  • SA21-9311-1 — Customer Support Functions, October 1978.

Common Faults

  • Processor card (J2) — same unobtainable gate arrays as the 5100's G2 card. Reseat before condemning. IBM's bring-up diagnostic halt codes point at specific cards, and the summary chart in the Diagnostic Aids section is the fastest way to narrow a dead machine down: the very first tests implicate H2, J2 and L2, and the ROS content and CRC test implicates E4 and F2.[3]
  • ROS cards — executable ROS on L2, feature ROS on K4, common and language ROS on F2, APL ROS on E4. IBM's own error-cause list maps the codes directly: error 001 or 005 is the common and language ROS card (F2); 002 and 014 are executable ROS (L2), the processor (J2) or read/write storage (M2); 007 is a CRC error; 008 a module ID error.[3]
  • 5114 8-inch diskette drive — belt ageing, head-load solenoid fatigue, spindle motor brush wear, and oxide shedding from period media. IBM error 045 "No Index" means no index pulse was sensed for 333 ms: either no diskette was mounted, or it was mounted backwards. Check that before suspecting the drive.[3]
  • Tape drive (Model 1) — belt and capstan, same as the 5100. The tape status byte lives at read/write storage address hex 8F and its eight bits are documented individually, so a tape fault can be narrowed down without a scope.[3]
  • CRT — same risks as the 5100.
  • Power supply — not a linear supply. IBM describes it, as on the 5100, as a transistor switching regulator, with the same five rails (+5, −5, +8.5, +12, −12 V), the same protection behaviour and the same five-second restart rule after an automatic shutdown.[3] The 5114 Diskette Unit is different — its supply is ferroresonant, not a switcher, and it has its own AC box. Both are covered on the IBM 5110 Capacitor Replacement Guide.

Software

The 5110 was aimed at IBM General Systems Division's small-business accounting market; IBM offered a basic accounting software bundle. Core International (Hal Prewitt) developed an extensive third-party application catalogue and, in 1981, a hard-disk subsystem and a CoreNet LAN add-on for the 5110 and 5120.[5]

John Titor Connection

The 5110 is the machine originally named in the John Titor IRC log of 14 October 2000 — the poster mentioned the 5110 four times before quietly switching to "5100" on the public forums in November 2000. Pamela Moore, a Titor correspondent, received a physical fragment of a 5110 label by post with an Orlando postmark, consistent with the IRC claim.[6] See the IBM 5100 page for full coverage of the Titor story and the System/370 emulator claim.

  • IBM 5110 at the Ridai Museum of Modern Science, Tokyo
    IBM 5110 at the Ridai Museum of Modern Science, Tokyo

References

  1. ↑ 1.0 1.1 Wikipedia, "IBM 5110". Tertiary; used for the marketing chronology, the first-customer-shipment story and the withdrawal dates. Those dates are sourced there to the IBM Hursley Museum's Hardware Announcements to 1987 list, whose URL no longer serves the PDF (it redirects to the museum home page), so they could not be confirmed against the underlying document during verification.
  2. ↑ IBM, "IBM 100 — The Personal Computer: the team", at ibm.com/ibm100/us/en/icons/personalcomputer/team/. Supports Bill Sydnes's presence on both programmes.
  3. ↑ 3.00 3.01 3.02 3.03 3.04 3.05 3.06 3.07 3.08 3.09 3.10 3.11 IBM, IBM 5110 Computer Maintenance Information Manual, SY31-0550-2, February 1979 — hosted on this wiki as IBM 5110 Maintenance Information Manual. Section 3 "Theory": Functional Units and the A1 board block diagram (which names every card by slot — processor J2, base I/O H2, executable ROS L2, feature ROS K4, common and language ROS F2, APL ROS E4, read/write storage M2/M4/N2/N4, display adapter G2, parallel I/O K2, I/O cable driver A2); the 5110 processor data flow; the I/O Control Block table giving the device addresses; the interrupt priority rule; the power chapter describing the supply as a transistor switching regulator and giving the trip points and the five-second restart rule. Section 2 item 272 (Y1 socket pin assignments and DC rail tolerances) and item 280 (I/O interface cable pin assignments, which show +5, +8.5, +12, −12 and −5 Vdc on the power connector). Section 4 "Diagnostic Aids": the bring-up diagnostic and its halt codes, the Diagnostic Control Program, the error-code and device-address summary, and the status-byte descriptions. Appendix A, 5110 specifications.
  4. ↑ 4.0 4.1 4.2 IBM, IBM 5110 System Logic Manual, SY31-0552-3, February 1979 — hosted on this wiki as IBM 5110 System Logic Manual. Sheet 445 "Parallel I/O", which draws the parallel I/O card (A1K2), its internal and external cables, the bi-directional drivers and receivers, the ATTN, IFC, EOI and DIO control lines, and the 24-pin external connector Y3, labelling the bus as the "IEEE Bus (bi-directional)". Sheet 480, "5110/5114 D.C. Power Distribution".
  5. ↑ Core International, 1981 5110 Disk brochure. The publisher's own site is long gone; the brochure survives only in the Internet Archive's Wayback Machine, which is not reachable from this wiki's verification tooling, so the brochure's contents could not be checked directly. The claim is therefore recorded as attributed, not verified.
  6. ↑ Wikipedia, "John Titor". Tertiary; used only for the chronology of the hoax and the 5110-before-5100 discrepancy in the IRC logs.

Further reading


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