The Commodore 128: The Most Versatile 8-Bit Computer Ever Made
by Ian Matthews of Commodore.ca
July 11 2003
Last Revised Dec 30 2018
NOTE: Your are in the TEXT ONLY version of our site; click HERE for our full Commodore 128 Page
Commodore 128 History:
In the summer of 1984 Commodore decided that
they needed a replacement for the amazingly successful C64. More
accurately they decided that the TED / 116 / Plus/4 / 264 Series was a
failure as a replacement for the C64.
This machine would be
Commodores last 8-Bit computer; after this they would produce only 16/32
Bit Amiga’s and IBM PC clones.
Customer reaction to Commodores
failure to provide native CP/M support in the C64 and (much worse) their
failure to provide C64 compatibility in the Plus/4 / 264 Series taught
Commodore engineers some hard lessons. Commodore’s founder and visionary,
Jack Tramiel, had quit months earlier and the new management team wanted
to just forget the Plus/4 / 264 Series fiasco. Fortunately, the engineers
knew they needed a new product and that product had better be compatible
with the best selling computer in the world, the C64.
Bil Herd got
the top job as128 lead Engineer because of his vocal criticism of the new
management teams lack of vision. “No one dreamed that C64 compatibility
was possible so, no one thought along those lines. I had decided to make
the next machine compatible with _something_ instead of yet another
incompatible CBM machine. (I won’t go into the “yes Virginia there is
Compatibility” memo that I wrote that had the lawyers many years later
still chuckling, suffice it to say I made some fairly brash statements
regarding my opinion of product strategy). Consequently, I was
allowed/forced to put my money where my mouth was and I took over the C128
project.”
bil_hurd_xmas_2003Under managements guidance, the first
C128 concept machines (pre-prototype) made no attempt at C64
compatibility. Bil recalls, “I looked at the existing schematics once and
then started with a new design based on C64ness. The manager of the chip
group approached me and said they had a color version of the 6845 if I was
interested in using it would definitely be done in time having been worked
on already for a year and a half… And so the story begins.”
Commodore needed its next computer to be a serious upgrade from the C64 if
it was to successfully battle its arch nemesis; it needed to keep Jack
Tramiel’s, Atari, from besting them with features in the their rumored new
“ST” line.
In 1982, Commodore released the worlds first
multi-processor personal computer, called SuperPET, but it was $2800
($6100 dollars in 2018) and targeted at the education / scientific
markets. The Commodore 128 was to be the worlds first mass market
multi-processor computer. It would also have two video subsystems, one of
which would allow it to connect to a TV.
A reviewer from Your
Computer magazine wrote “The dowdy shoebox image of the Commodore 64 has
been replaced by a slim line beige console that any style-conscious
businessman should be pleased to have on his desk. A full size typewriter
style keyboard has 92 keys, that travel and locate well.” The 128’s 80
column display mode would produce 640×200 which was better than the CGA
mode that IBM PC’s could produce even in the early 1990’s! This new an
powerful machine would act as three completely separate computers in one:
Commodore 128 Mode 2Mhz Speed (8502 CPU), 128K Memory, very nice 80×25
RGB display, advanced Basic 7.0
Commodore 64 Mode 1Mhz Speed (6510
emulation in the 8502 CPU), 99.8% compatible with 64 hardware and
software, accessed by booting the machine while holding down the Commodore
key or typing GO 64
Commodore CP/M Mode 1-4Mhz Speed (Zilog Z-80 CPU),
100% compatible with the huge volume of CP/M business applications such as
Turbo Pascal and WordStar (an excellent program I used personally for
years on a Sanyo MBC555 !) Note that the Z-80 processor was originally
spec’d by Commodore management to be the same external expansion cartridge
used on the C64. However, to resolve several other engineering problems,
Bil Herd designed the Z-80 into the main board. This mode required CP/M
software disks to be loaded on boot up.
All this would sell for an
initial price of just $300 ($650 in 2018 dollars); half of the Commodore
64 price when it was introduced two years earlier.
The Chips:
MOS 8502 CPU – Yet another derivative of the 6500 series
Zilog Z-80
Improved version of Intel 8080 CPU designed by the same Intel engineer
MOS 8563 CRCT / VDC – Video Display Chip 80 column x 25 rows 640×200 (128
mode only)
MOS 8564/6 VIC – Video Interface Chip (NTSC / PAL) – used in
40 column x 25 row
MOS 8721 FLPA
MOS 8722 MMU – Memory Management
Unit
MOS 6581 SID – Sound Interface Chip
MOS 6526 CIA – Complex
Interface Adaptors (2 of them!)
commodore-c128_80col_basic_screen_shot
Commodore 128 in 80 Column Mode
This technically complex machine
would present serious engineering and marketing challenges to any company.
Bil Herd recalls “It was sometime in September (1984) when we got 8563
(new 40/80 column color video chip) Silicon, good enough to stick in a
system. …One concern we had was it occasionally blew up…. big time…. turn
over die and then smell bad….. But then all of the C128 prototypes did
that on a semi regular basis as there wasn’t really any custom silicon
yet, just big circuit boards plugged in where custom chips would later go…
but you can’t wait for a system to be completed before starting software
development. When this problem still existed on Rev 4 we got concerned. It
was at this time that the single most scariest statement came out of the
IC Design section in charge of the ’63. This statement amounted to ‘you’ll
always have some chance statistically that any read or write cycle will
fail due to (synchronicity)’ “.
“Synchronicity problems occur when
two devices run off of two separate clocks, the VIC chip hence the rest of
the system, runs off of a 14.318Mhz crystal and the 8563 runs off of a
16Mhz Oscillator. Now picture walking towards a revolving door with your
arms full of packages and not looking up before launching yourself into
the doorway. You may get through unscathed if your timing was accidentally
just right, or you may fumble through losing some packages (synonymous to
losing Data) in the process or if things REALLY foul up some of the
packages may make it through and you’re left stranded on the other side of
the door (synonymous to a completely blown write cycle). What I didn’t
realize that he meant was that since there’s always a chance for a bad
cycle to slip through, he didn’t take even the most rudimentary protection
against bad synchronizing. …As it turns out the 8563 instead of failing
every 3 years or so (VERY livable by Commodore standards) it failed about
3 times a second.”
In addition the yield on these video chips was
about .001%. Commodores chip division MOS Technologies could only get
three or four working chips the per run. “A run is a half-Lot at MOS and
costs between $40,000 and $120,000 to run. Pretty expensive couple of
chips.”
As if these problems were not enough, the power supply
needed to be adjusted for each chip or they would literally burn up. “No
single custom chip was working completely as we went into December (1984)
with the possible exception of the 8510 CPU… At this point all I did have
to lose was a HUGE jar of bad 8563’s. (One night a sign in my handwriting
“appeared” on this jar asking “Guess how many working 8563’s there are in
the jar and win a prize.” Of course if the number you guessed was a
positive real number you were wrong.)”
consumer-electronics-show-registration-1983With only five or six weeks to
go until the January Consumer Electronics Show in Vegas “…finger pointing
was in High swing, (the systems guys should have said they wanted WORKING
silicon) with one department pitted against the other, which was sad
because the other hardworking chip designers had preformed small miracles
in getting their stuff done on time… …Managers started getting that look
rabbits get in the headlights of onrushing Mack trucks, some started
drinking, some reading poetry aloud and the worst were commonly seen doing
both. Our favorite behavior was where they hid in their offices. It was
rumored that the potted plant in the lobby was in line for one of the key
middle management positions.”
Unbelievably, in this time of
crisis, both MOS chip designers went on Christmas vacation and “…a
sprinkler head busted and rained all over computer equipment stored in the
hallway. Engineering gathered as a whole and watched on as a $100,000
worth of equipment became waterlogged…. I can honestly say that it didn’t
seriously occur to me that we wouldn’t be ready for CES… here were just
too many problems to stop and think what if.”
Von had wisely chosen
not to try to follow all of the current Revs of the 8563, instead he
latched onto a somewhat working Rev4 and kept if for software development.
Later we would find out that Von, to make the 8563 work properly, was
taking the little metal cup that came with his hot air popcorn popper (it
was a buttercup to be exact) and would put an Ice cube in it and set it on
the 8563. He got about 1/2 hour of operation per cube. On our side there
was talk of rigging cans of cold spray with foot switches for the CES
show.”
Bil Herd stated that a number of “odd engineering fixes”,
often conceived after consuming a few beers at the bar beside the MOS
factory, resulted in seemingly insurmountable problems being quickly
resolved. The most important of these ‘fixes’ was the integration of a
Z-80 CPU into the main board. In addition to resolving several taxing
electronic problems, it elevated the C128 into the realm of the business
computer. “A True Miracle and was accompanied by the sound of Hell
Freezing over, the Rabbit getting the Trix, and several instances of Cats
and Dogs sleeping together. This was the first time that making CES became
a near possibility. We laughed, we cried, we got drunk.”
“We
averaged 1-3 of these crises a day the last two weeks before CES. Several
of us suffered withdrawal symptoms if the pressure laxed for even a few
minutes. The contracted security guards accidentally started locking the
door to one of the development labs during this time. A hole accidentally
appeared in the wall allowing you to reach through and unlock it. They
continued to lock it anyways even though the gaping hole stood silent
witness to the ineffectiveness of trying to lock us out of our own lab
during a critical design phase. We admired this singleness of purpose and
considered changing professions.”
“We finished getting ready for
CES about 2:00am in the morning of the day we were to leave at 6:00am.”
“Advertisements in the Las Vegas airport and again on a billboard
en-route from the airport inform us that the C128 has craftily been
designed to be expandable to 512K. Now it had been designed to be
expandable originally and had been re-specified by management so as to not
be expandable in case next year’s computer needed the expandability as the
“New” reason to buy a Commodore computer. That’s like not putting brakes
on this years model of car so that next year you can tote the New model as
reducing those annoying head-on crashes.”
You can see in the
advert to the right that a 512K expansion was eventually made, but not by
Commodore. This was from Berkely Softworks in 1990!
"Upon arriving
at the hotel we find that out hotel reservations have been canceled by
someone who fits the description of an Atari employee. Three things occur
in rapid succession. First I find the nearest person owning a credit card
and briskly escort her to the desk were I rented a room for all available
days, second, a phone call is placed to another nearby hotel canceling the
room reservations for Jack Tramiel and company, third, several of those
C64’s with built in monitors (C64DX’s??? man it’s been too long) are
brought out and left laying around the hotel shift supervisors path
accompanied by statements such as “My my, who left this nifty computer
laying here… I’d bet they wouldn’t miss it too much”.
“The next day
we meet up with the guy who developed CPM (Von) for the C128. As I
mentioned earlier, someone forgot to tell him about the silly little
ramifications of an 8563 bug. His ‘puter didn’t do it as he had stopped
upgrading 8563s on his development machine somewhere around Rev 4 and the
problem appeared somewhere around Rev 6. As Von didn’t carry all the
machinery to do a CP/M rebuild to fix the bug in software, it looked like
CP/M might not be show-able. One third of the booth’s design and
advertising was based on showing CP/M. In TRUE Animal fashion Von sat down
with a disk editor and found every occurrence of bad writes to the 8563
and hand patched them. Bear in mind that CP/M is stored with the bytes
backwards in sectors that are stored themselves in reverse order. Also
bear in mind that he could neither increase or decrease the number of
instructions, he could only exchange them for different ones. Did I
mention hand calculating the new checksums for the sectors? All this with
a Disk Editor. I was impressed.”
“Everything else went pretty
smooth, every (power) supply was adjusted at the last moment for best
performance for that particular demo. …On the average, 2 almost working
8563’s would appear each day, hand carried by people coming to Vegas.
Another crisis, no problem, this was getting too easy.”
The
Peripherals:
Commodore did not produce many peripherals designed
exclusively for the 128 line because they did no have to. They relied
primarily on existing C64 devices like the 1541 floppy drive. An exception
was the Commodore 1902 monitor for $400 (which is $875 in 2018 dollars and
was $100 more than the price of a new C128!) which was required to use the
new 128’s advanced 80 column mode. The C1750 massive 512K RAM Expander was
another new product. The most anticipated new peripheral was the 1571
double sided floppy drive which, at 360K, provided more than double the
capacity of the 1541. Much more importantly it was a whopping 7 to 10
times faster!
Many Bulletin Board Systems (BBS’s – pre-internet for
those of you who were born after 1980) also jumped on the C128 Mode
bandwagon. There are a number of historians who site Commodore as the
unsung development partner of the Internet. While it is certainly true
that the US military and several universities developed ARPANET, its
transition into the internet would not have been so rapid had online
communities not been created with extensive use of Commodore hardware: the
amazingly inexpensive VIC Modem (and its decedents the 1600, 1650, 1670
and 1680) combined with powerful C128 Mode functionality allowed thousands
of BBS’ to spring up from nothing. The 128 produced:
a large supply
of online information
consumer awareness, which created demand, and
telecommunication capacity and skills
all of which are were required to
develop and commercialization the Internet
The Commodore 128D:
In an effort to extend the life of this powerful multi-talented machine,
Commodore introduced a slight derivative of the 128 called the Commodore
128D in 1987. The idea was to make a cleaner, smaller foot print for the
128 so that it might appeal to the small business segment dominated by IBM
at the time. Commodore 128D models looked allot like Apple Mac computers
of the late 1990’s. They came in a square desktop box, featuring an
integrated a front loading Commodore 1571 5.14″ high capacity floppy disk
drive, and a separate keyboard. A monitor could sit nicely on top of this
chassis, again reducing desk space requirements and clutter. The price of
this system, just $500 ($1100 in 2018 dollars), a third the price of an
IBM PC.
In a cost saving effort, D’s were manufactured with less
expensive “upgrade” versions of the SID (sound) chip, called the 8580 SID
and were sometimes referred to a 128DCR’s (Cost Reduced).
The first
European 128D’s chassis were made of plastic. They came with a keyboard
dock and carry handle! The North American model came in standard beige
steel chassis’ without the carry handle or keyboard dock.
On an
amusing note, I have often been asked questions from non-Commodore
collectors about a super-rare prototype called a Commodore 1280. Of course
this is simply a misreading of the Commodore 128D name.
Today (in
2003), 128D models are highly sought after by collectors and enthusiasts,
usually garnering more than triple what a standard 128 sells for.
The People of the Commodore 128:
Early in the process, a team of
experienced hardware and software engineers were assembled and they left
their personal mark on the their machine with an “easter egg”. Type SYS
32800,123,45,6 on your 128 and you will see a small list of development
credits. Note the spelling of the word Hardware; presumably a tribute to
Bil Herd. The image on the left was created with the amazing WinVice
Commodore emulator available from many sources including download from
Commodore.ca download menu.
Bil Herd explains “The names of the
people who worked on the PCB layout can be found on the bottom of every
PCB.”
Bil Herd Original design and hardware team leader.
Dave
Haynie Integration, timing analysis, and all those dirty jobs involving
computer analysis which was something totally new for CBM.
Frank Palaia
One of three people in the world who honestly knows how to make a Z80 and
a 6502 live peacefully with each other in a synchronous, dual video
controlled, time sliced, DRAM based system.
Fred Bowen Kernal and all
system like things. Dangerous when cornered. Has been known to brandish
common sense when trapped.
Terry Ryan Brought structure to Basic and
got in trouble for it. Threatened with the loss of his job if he ever did
anything that made as much sense again. Has been know to use cynicism in
ways that violate most Nuclear Ban Treaties.
Von Ertwine CPM.
Sacrificed his family’s popcorn maker in the search of a better machine.
Dave DiOrio VIC chip mods and IC team leader. Ruined the theory that most
chip designers were from Pluto.
Victor MMU integration. Caused much
dissention by being one of the nicest guys you’d ever meet.
Greg Berlin
1571 Disk Drive design. Originator of Berlin-Speak. I think of Greg every
night. He separated my shoulder in a friendly brawl in a bar parking lot
and I still cant sleep on that side.
Dave Siracusa 1571 Software. Aka
“The Butcher”
Special note: “RIP: HERD, FISH, RUBINO”
“The
syntax refers to an inside joke where we supposedly gave our lives in an
effort to get the FCC production board done in time, after being informed
just the week before by a middle manager that all the work on the C128
must stop as this project has gone on far too long. After the head of
Engineering got back from his business trip and inquired as to why the
C128 had been put on hold, the middle manger nimbly spoke expounding the
virtues of getting right on the job immediately and someone else, _his_
boss perhaps, had made such an ill suited decision. The bottom line was we
lived in the PCB layout area for the next several days. I slept there on
an air-mattress or was otherwise available 24 hours a day to answer any
layout questions. The computer room was so cold that the Egg McMuffins we
bought the first day were still good 3 days later.”
The End of the
Commodore 128:
The 128 went on to be a notable success for Commodore
but not because of its new power. Unfortunately most software developers
ignored the new and advanced C128 Mode functionality. Why develop software
for a new, relatively small product like 128’s native mode when you can
write software for the wildly successful C64 and know that your code will
function on a 128 operating in 64 mode. There were some notable
exceptions, such as the Graphical User Environment called GEOS which
created a powerful 128 Mode version.
Before its demise in 1989, the
Commodore 128 sold a respectable four million units but this number could
have been dramatically larger. Much like the Amiga to come, Commodore was
incapable of promoting the C128 to the appropriate target markets. 128’s
were insanely inexpensive when compared feature for feature with its the
competition of the day and in the end they sold about 10 times their
nearest competitor, the Apple IIc. If Commodore had developed and pushed
the “D” models to the small business market in 1986, the 128 could have
been a serious contender in that space.
The last gasp was a very
small production run Commodore 128CR’s (Cost Reduced) released in North
America in 1988 or 1989. They were identical to the 128DCR except they did
not have an integrated floppy drive. I have never seen one of these units…
not even a picture! If you have one, please email a picture to us and we
will add it to this site with credit to you.
On a sad note, the
128’s CP/M Mode was almost never used because CP/M was quickly losing
ground to Microsoft Disk Operating System (MS DOS) by then running at
version 2. MS-DOS was of course popularized by the IBM PC and seemingly
endless line of IBM clone machines. Business developers had all but
abandoned the old standby CP/M in favour of the new and rapidly expanding
DOS market. The Commodore 128 was CP/M’s last big play, but the 128 just
did not have the market penetration to keep CP/M alive.
POSTMORTEM
C128:
The Commodore 128 was a pretty cool machine and as we mentioned
in the article, it still has a serious following. When researching our
November 2018 update of this page, we were pleased to here someone is
working on a new C128 project.
There isn’t much information on
128RM but the graphics show it is “The 128 Remastered” and the forum
thread for this indicates it is designed to fit into a Commodore 64
chassis.
In April 2016 the designer said “…I do not want to
postpone the main chips (MOS chips) because I’m already at the 7th
‘Rebuilding from 0’, aka. ‘MK7’ (see the back of the board).” so whoever
it is, he is serious. In October 2018 he wrote “To put it briefly:
“THE128RM” is in the final version. 🙂 (I will certainly optimize this
before the “release-version”). Currently I’m waiting for the
manufacturer.”
In November 2018 he explained that the board will
come with everything but the MOS chips “…no bare board. All components are
on it. You just have to fill the sockets.” and few people on the forum are
bouncing around prices ranging from 50€ to 200€ but the designer has not
commented yet. Fortunately, he does have a website
http://the128rm.com but, as of this
writing, there is nothing on it but single picture and COMING SOON notice.
We contacted the designer at the end of November 2018 and Peter
provided us with the pictures to the right (which are 1 version out of
date) and told us:
I am currently waiting for the manufacturer to
finish, hopefully the last version. I am thinking of to start the
pre-order this year. Reseller’s are welcome! 🙂
I think we don’t
have any legal issues. I am not using the Commodore brand name and using
an modified version of the schematics. So there shouldn’t be any.
Beyond the 128RM, we also found some cool new hardware items on eBay. Most
notably the Commodore 128 Diagnostic Cartridge. The seller describes it
like this:
NEW V2 – Commodore 128 Diagnostic Cartridge 785260 GOLD
ENIG C128 128D 128DCR in stunning black! This new Version 2 of our 128
diagnostic cartridge features a decoupling capacitor on board. It exists
to filter undesired noise from your power supply.
This is uniquely
designed specifically for the Commodore 128/128D/128DCR operating in 128
mode! That’s right, this diagnostic cartridge will test your 128 while
operating in 128 mode… not 64 mode.
Commodore 128 Chronology:
Italicized lines refer to key moments in history that are not Commodore
related
1984
January 13th – Commodore shows off prototype 264 and
364 at CES and indicates they should be in production by June
January
15th – Commodores founder, visionary and CEO, Jack Tramiel quits Commodore
with secret plans to buy the near bankrupt Atari
April – Commodore
launches its first IBM clone, the Commodore PC, at the Hanover Fair in
Germany
April – Commodore shows the Commodore Z8000 at the Hanover Fair
in Germany
Mid-Summer – Commodore decides the Ted / 264 / 116 / Plus/4
Series will not sell as a replacement to the C64
September – Bil Herd
appointed lead designer on C128 project in an effort to get a new machine
ready for show at CES in Las Vegas, the 2nd week of January 1985
November – New chips are still not close to stable
December – Z-80 CPU
incorporated into motherboard design – chip problems start getting
resolved quickly
December – A 16K version of the 264 called the
Commodore 116 is for sale (at least in Germany)
Intel introduces the
80186, 80188, and 80286 processors
Motorola unveils its 68010 CPU chip
1985
January – The last VIC-20 rolls off the line and into the history
books
January – Serious design problems still exist but are being
resolve daily
January – C128 prototypes completed at 2am just 4 hours
before the trip to CES
January – Commodore’s hotel rooms have been
cancelled, possibly by their former boss turned competitor, Jack Tramiel
January – Prototypes shown at CES are unstable, going through two 8563
video chips per day, but the audience is unaware of this
Januray –
Atari introduces the 130ST: 128KB RAM, 192KB ROM, 512 color graphics, MIDI
interface, and mouse for $400.
January – Atari introduces the 520ST:
512KB RAM, 192KB ROM, 512 color graphics, MIDI interface, and mouse for
$600.
June / July – C128 production begins and units are to sell for
just $300
April – IBM stops production of the IBM PCjr
May –
Microsoft demonstrates Microsoft Windows 1.0 at Spring Comdex. Release
date is set for June, at a price of US$95
September – Apple Computer
co-founder Steve Jobs resigns from Apple Computer and founds NeXT
Incorporated
Commodore stops production of the 64 several times
(presumably in favor of the much more powerful 128) but restarts it
because of demand
1986
January – Apple Computer starts producing the
Macintosh Plus, with 1 MB RAM, support for hard drives, a new keyboard
with cursor keys and numeric keypad, for $2600 ($5200 in 2018 dollars)
Design of the 128D, business style case with neatly integrated 1571 floppy
disk drive begins
Germany celebrates its 1,000,000 C64 with a Golden
Jubilee version
March – Microsoft goes on the stock market at $21 per
share. This raises $61 million ($125 million in 2018 dollars).
June –
In an effort to revitalize sales, Commodore releases a sleek new 128 like
case, changes the name to 64C, and bundles it with GEOS
August – Intel
ships the 80386
September – Plus/4 was in full liquidation were selling
for a mere $79 ($160 in 2018 dollars)
September – IBM announces the IBM
PC-XT Model 286, 640KB, 20MB hard drive, 1.2MB floppy, serial/parallel
ports, and keyboard for the low low price of $4000 ($8100 in 2018 dollars)
1987
128D’s hit retail stores in Europe and North America for about
$500 ($950 in 2018 dollars)
February – Commodore announces the Amiga
500 and 2000
April – IBM and Microsoft announce Operating System/2 –
OS/2.
June – Atari releases the Atari XE Game System, with 64KB RAM,
supporting 256KB game cartridges
October – Microsoft ships Windows 2.0
intel-80486-ibm-comdex-chicago1989
Production of all 128 models stops
Total Commodore 128 sales are in the four million unit range about 10
times that of it’s nearest competitor the Apple IIc
Intel introduces
the 80486 microprocessor at Spring Comdex in Chicago. It integrates the
80386, 80387 math coprocessor, and adds a primary cache. It uses 1.2
million transistors. Initial price is US$900 ($1600 in 2018 dollars)
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