IBM 5100

From: Fred Cisin <>
Date: Mon Aug 16 16:19:45 2004

Does that mean that there are doubts about the validity of some
of John Titor's claims??

On Mon, 16 Aug 2004, Christian Corti wrote:

> On Mon, 9 Aug 2004, emx wrote:
> > Here is a post that was made on one of the web sites dedicated to John
> > Titor.
> I will comment on this post:
> > I'm not sure if anyone else has posted anything about the 5100, but
> > this machine was very interesting. In the early 80's, I worked on a
> > slightly upgraded version of the 5100 called the 5110. The 5100/5110
> > machine executed code intended for IBM mainframes of the time (System
> > 360/370) via a simple processor that emulated the old 360/370 CPU.
> This is wrong. The PALM processor (as used in the 5100/5110) has its own
> design and its own microcode and machine code. It does NOT execute any
> other microcode other than that programmed into a ROS on the CPU card. The
> "frontend" languages APL or BASIC are indeed written in other machine
> code. In order to run these interpreters, a program written in PALM
> machine code is run (part of the Executable ROS) to interprete the
> interpreter. That's why BASIC/APL is running so slowly on these machines.
> The PALM CPU itself is a full 16 bit processor with 8 bit ALU and 18 bit
> data path (incl. parity bits for each byte).
> > Languages, such as APL or VS BASIC were programs written in machine
> > language, that were, in turn, interpreted by the CPU in a lower level
> > language called 'Microcode'
> If microcode == machine code, then yes.
> > Microcode allowed IBM to modify or enhance basic machine language
> > instructions at will after the mainframe was delivered to the
> > customer. The concept was 'ship an initial version of the 'machine',
> > but allow upgrades as they were developed without the wholesale
> > replacement of hardware'. To change a basic instruction in
> > microprocessors today usually requires a physical change in the chip,
> > since all instructions are 'hard-wired' into the design of chip.
> You can't change the microcode of the PALM processor. That would be like
> changing the microcode of e.g. a MC68000.
> And today's processors are all microcoded, i.e. you DON'T have to change
> the wiring of the processor, but only the so called microprogram for
> exactly this one instruction. Well, the problem is that the microprogram
> ROM is located on the CPU chip...
> > The core design of the 5100 series machine was an emulator of the old
> > IBM 360/370. The CPU of these machines was designed to execute the
> No, the SCAMP was designed to run a subset of the IBM 1130 processor. The
> PALM processor really has nothing in common with either the 1130 or any
> 360/370.
> > mainframe. It was not a fast machine, but it worked, and the
> > performance of the old 5100 was good enough to run many of the same
> > applications we had developed on our $10 million twin IBM 370
> In my opinion the PALM processor is quite fast, e.g. around 500k
> instr./sec.
> > mainframe installation. APL and VS BASIC apps ran with little or no
> > modification, except for storage device definitions, which were
> > limited to 300KB 8" floppies or 150KB streaming tape cartridges.
> Well, the 300kB are 1,1MB (DS/DD) and the 150kB are more like 220kB (or
> 500kB with DC600 cartridges).
> Again: For more information have a look at
> Christian Corti
Received on Mon Aug 16 2004 - 16:19:45 BST

This archive was generated by hypermail 2.3.0 : Fri Oct 10 2014 - 23:36:34 BST