My Vintage Dream PC

Discussion in 'Computer Information' started by GreenXenon, May 18, 2009.

  1. Well, the earlier machine was a B300, and IIRC, they did use it for some
    of the B5000 development internally. B300 was a descendent of the Electrodata
    Scott Lurndal, Jun 10, 2009
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  2. There is that story of the woman who was completely against drinking
    alcohol, but *loved* to run the ditto machine.
    Walter Bushell, Jun 10, 2009
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  3. GreenXenon

    Peter Flass Guest

    Or, if you really didn't want an assembler, why not code in Algol or
    whatever and cross-compile?
    Peter Flass, Jun 11, 2009
  4. But cross-compile it using what?

    If they didn't have an assembler, it's likely they didn't have a compiler
    backend just lying around, either.

    One might, however, hope that the "first compiler" referenced above wasn't a
    compiler for the entire language. Anyone know?

    Roland Hutchinson

    He calls himself "the Garden State's leading violist da gamba,"
    .... comparable to being ruler of an exceptionally small duchy.
    --Newark (NJ) Star Ledger ( )
    Roland Hutchinson, Jun 11, 2009
  5. I agree with Mr. Pfeiffer. If an assembler is developed, then *no* more
    programming in machine code. But *when* was the assembler developed???

    I knew an "auld fart" who took an early computer course at Michigan
    State University in 1954. He was programming some incarnation of an
    Illiac. In this early course, they programmed in *absolute* machine
    code. He talked about adding several no-ops at the end of each loop, so
    that more instructions could be added *without* changing the branch
    address by simply replacing no-ops.

    At that time for this machine, they used "KSNJFL" instead of "ABCDEF"
    for the last six digits of hexidecimal. And so the "king size numbers
    just for laughs" or "kind souls never josh fat ladies" mnemonics.
    Charles Richmond, Jun 11, 2009
  6. GreenXenon

    Joe Pfeiffer Guest

    Early 1950s. Granted, that's an assembler for a different computer.
    But I just can't believe that when there were something like five (or
    fewer) computers in the world, such a small community couldn't do favors
    for each other.
    And I'd have to look it up, but there was actually a reason why the
    character encoding they were using made KSNJFL sensible. One could
    argue that meant the encoding wasn't sensible....
    Joe Pfeiffer, Jun 11, 2009
  7. GreenXenon

    JosephKK Guest

    Even on an isolated system there will be exactly one NTP master, which
    may receive reasonably synchronized time in other (fully
    unidirectional) ways. Moreover, with group synchronized time that is
    asserted at each Boot/IPL the synchronization issue almost completely
    goes away (short of intentionally lying to every computer and
    preventing any real world input to the contrary). Even then it still
    effectively goes away for that equipment group.
    JosephKK, Jun 11, 2009
  8. GreenXenon

    JosephKK Guest

    Is it possible to purchase so many as 3 "dead" 35s (or 9100s) from
    JosephKK, Jun 11, 2009
  9. GreenXenon

    JosephKK Guest

    But i never liked the smell of the diazo process running.
    JosephKK, Jun 11, 2009
  10. That is very small project in terms of software. Even my ASIC/FPGA
    testbenches are sometimes 5x bigger ;)
    The problem is how to define these interfaces. Modules have interactions
    at different levels of hierarchy and trying to keep all those in mind
    during design phase is difficult. When you approach the millions
    of lines of code, then the documentation also is in the range of
    (ten)thousands of pages. Trying to keep that kind of monster in
    control is not easy.

    Unit level interaction problems are quite common, they are usually
    caused by misunderstandings of the big picture. Of course also unit
    level problems are common, they could be mitigated via module testing
    etc. but that costs money. The development process is always compromise
    between time to market, price and reliability. Maybe in military
    projects the time and money are not a problem ;)

    Kim Enkovaara, Jun 11, 2009
  11. And you trust your filesystem, operating system, backup media,
    manual operations for release versioning etc. How do you know
    that 5 year old release file xyz is not corrupted? In VCS systems
    metadata usually contains crc or hash of the version, and the
    database integrity can be checked. Do you have manual pictures
    of the relationships of the code, or is it so simple that it is
    in one linear progression, which is not normal.

    At least in VCS systems usually mere mortals can't delete any
    versions at any time. In that way a user can not do any real damage.
    And of course those systems are also backed up, maybe replicated
    for hot switch-overs if the system is not healthy etc.

    This is not rocket science, VCS systems have been in use for a long
    time and for a reason.

    Kim Enkovaara, Jun 11, 2009
  12. GreenXenon

    JosephKK Guest

    I have worked with plenty of machines with no ROM whatsoever. You had
    punch in by hand the most trivial tools, then use that to add a
    loader, maybe 50 words or so (of 150 to 200 bytes on a byte oriented
    machine). Then, on the machines i used, a paper tape could load any
    useful program. Once you had some ROM to work with booting/IPL got
    much easier.
    JosephKK, Jun 11, 2009
  13. How about ClearCase mvfs? In mvfs you can probe older file versions, or
    even versions from different branches. Checked out files can be edited
    freely. The hard part of creating a file version is left to additional
    utility that is used to checkout, checkin and delete the version
    controlled files.

    For example in mvfs you could do "less [email protected]@/main/mybranch/3" or
    "less file.c" for the default version (latest, or any other specified by

    Kim Enkovaara, Jun 11, 2009
  14. Hence "There's always time to do it over and never time to do it
    Ahem A Rivet's Shot, Jun 11, 2009
  15. The big difference between cars and programs is that programs are
    generally one off designs done under time pressure with urgent spec changes
    at the last minute. There are usually glaring errors in every stage from
    requirements to final product - some of the errors cancel each other out,
    many are never found.

    That being said - my BSD boxes run reliably for as long as I care to
    run them, start reliably whenever I choose to start them, opening vi never
    causes sylpheed to fail (to pick two applications at random). Most unixish
    systems will run crashme indefinitely (crashme is a delightful program that
    populates a chunk of memory with random numbers and then executes it after
    setting handlers for all the error signals this behaviour is likely to
    produce) without causing problems to anything on the system.

    In other words there is reliable software and it has become
    reliable through pretty much the same process that cars and jet planes have
    become reliable - refinement in light of experience. Cars were far less
    reliable in 1920 or even 1950 - it wasn't until well into the 1970s that
    electric start was reliable enough to dispense with the cranking handle
    completely. They have become reliable because over the years engineers have
    been learning about, understanding and removing the causes of unreliability.
    Ahem A Rivet's Shot, Jun 11, 2009
  16. GreenXenon

    Peter Flass Guest

    There's always a question of how much "scaffolding" you want to take the
    time to write. If you have one module in isolation you have to write
    code to provide its inputs and do something with its outputs. When you
    do that, you still have a potential problem with misinterpretations and
    bugs, so you're not much further ahead than if you tested large chunks
    of code all together.
    Peter Flass, Jun 11, 2009
  17. GreenXenon

    Peter Flass Guest

    I can't exactly recall that PDP-11 video on U-Tube. Didn't they have to
    toggle in the initial bootstrap in order to load the paper tapes?
    Peter Flass, Jun 11, 2009
  18. GreenXenon

    jmfbahciv Guest

    The university I went to had a grad level course which consisted of
    writing a compiler. There were no classes.

    jmfbahciv, Jun 11, 2009
  19. GreenXenon

    jmfbahciv Guest

    Nor complicated like a monitor can be.

    jmfbahciv, Jun 11, 2009
  20. GreenXenon

    jmfbahciv Guest

    <grin> I once had a secretary who would condemn anybody
    who drank beer but would figure out how to spend an hour
    making ditto copies.

    jmfbahciv, Jun 11, 2009
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