From: dillon@overload.Berkeley.CA.US (Matthew Dillon)
Newsgroups: comp.sys.next.advocacy
Subject: Re:  End of NeXT
Distribution: world
Date: 4 Jan 93 11:47:20 PST
Organization: Not an Organization

In article <1993Jan4.111135.29283@cs.tu-berlin.de> marcel@opal.cs.tu-berlin.de (Marcel Weiher) writes:
>dillon@overload.Berkeley.CA.US (Matthew Dillon) writes:
>
>>    postscript despite the fact that their own laser printer stuffs rasters
>>    and despite the fact that raster conversion is simple (that is, support
>>    for non-postscript printers must be hacked in rather then go through
>>    NeXT's .PPD files).  Consider the fact that it is certainly possible to
>
>PPDs only describe PostScript printers.  Also, 3.0 supports some Dot matrix
>printers.  Why not more?  I'd hazard the guess that it's because there exists
>a third party solution, called Dots.  (Actually, I've one in the works myself,
>better of course,  but have more pressing projects.)

    3.0 supports a hack for one particular bitmap format and has no where
    near the flexibility required to support raster printers in general.
    And don't get confused... Dots came out long after NeXT should have
    been supporting raster printers.  Printer drivers are things that
    should be supportable by NeXT in a relatively seemless way, and that
    simply isn't true when it comes to dot matrix printers.  While I do not
    expect NeXT to actually write the drivers for every printer in
    existance, I do expect them to write and document their printer driver
    interface such that it would be relatively simple for people to add
    their own drivers.

    Printer drivers should NOT be costly third party products!	I'm not
    about to throw X hundred dollars at a printer driver when it's so
    potentially simple to write one (if only NeXT would support them
    properly).	And, in fact, I don't... I use the PD HP500 driver and
    apart from the fact that I can't touch any parameters through NeXT's
    standard printer interface, I can print with it just fine.	My
    complaint is all the garbage the poor guy who wrote that thing had to
    go through to support the HP, something NeXT could have fixed and
    should fix.

>>    printers', i.e. a NeXT-specific printer, requiring nothing more then a
>>    shorter cable, and still be able to run the SAME port at standard
>>    speeds for standard parallel printers. NeXT, going with a ludicrous
>>    custom 'printer' port and then trying to explain it away as being
>>    better on technical grounds is idiotic. The current scheme forces
>
>Would you care to back this statement up with facts?  I have heard of NO
>printer engine being driven by a standard parallel port.  All the
>laser printers with a parallel port need onboard memory + controller,
>enough for a full page if it's full page graphics.

    Laser printers need memory for a full page... well, actually, that's
    not quite true if you can guarentee a minimum transfer rate on the
    interface port.  But, true, current printers do need the memory and
    it's a hellofalot LESS then what they would need for the equivalent in
    postscript.  Memory != processing power, however, and going from 64KB
    to 16MB of ram does not significantly increase the complexity of the
    board whereas going from a relatively simple processor (68000) to a
    relatively complex processor (68332, DSP, etc...) results in a four
    fold cost increase at a minimum.

    However, I was not restricting the argument to laser printers...
    ink-jet (or dot matrix) printers do not need much memory, just enough
    for one swath of the print head.  The processing engine for that costs
    less then $20 including applicable memory in quantity.

    As far as facts go, keep in mind that while a parallel port does not
    use differential data lines, neither does IEEE-488, and IEEE-488 CAN
    EASILY GO AT 1MByte/sec.  The only difference between IEEE-488 and a
    parallel port electrically (not talking protocols here) is the
    termination and drive characteristics.

    The basic requirements to run a parallel port fast are already met---
    separate ground for each data line, handshake signals already
    available. Since a parallel port is NOT a drop network like IEEE-488,
    you need only restrict the maximum cable length and use an edge-to-edge
    protocol on the handshake lines instead of level-to-level to get higher
    speeds out of it.  Needless to say, that small difference is
    accomodatable with a few gates inside an ASIC (to support both standard
    and fast mode).

    Theoretically, restricting the interface to one end-to-end cable, it is
    possible to go relatively fast using standard low cost HCMOS logic
    (read: $0.50 driver chips).  I have, personally, with properly
    terminated HCMOS logic, run at 5 Mbits/sec over 2 meters point to point
    (not drop).  8 data lines == 5MByte/sec. I have not done this over a
    standard parallel port or cable since you need DMA, but the project was
    almost electrically equivalent (only difference being drive and
    termination, and that is upward compatible).

>>    non-NeXT printers to use the serial port since no parallel port is
>>    available.	This results in potentially poor performance for non-NeXT
>>    printers the fault of which is the NeXT, not the printer.
>
>Yes, I would like to have a parallel port, too.  But do remember that
>Sun just added one recently (I don't know about the other workstations)
>and Macs still don't have them.

    Is that an Excuse?	Lets put it another way... everyone has them except
    the Mac and the NeXT.

>>    Frankly, I don't give a damn about NeXT's laser printer.
>>    price/performance arguments aside, there is simply nothing special
>>    about it that I can see that isn't possible with other printers using a
>>    more standard interface.	All this crap about it being 'just an engine'
>>    is just that...crap.  There is no reason to require one to spout
>
>That's a strong statement,and as far as I know, "just crap".  The NLP is
>"just an engine", the reason you have to have a custom interface is
>because there is NO memory on board, therefore you have to feed the
>laser engine with an absolutely CONSTANT DATA RATE.  Just high speeds
>are not enough.  By the way, the interface is not parallel.

    So why isn't the NeXT laser printer half the price of the equivalent HP
    laser printer?  It sounds to me like someone has been pulling your
    leg... not in what isn't inside the NeXT Laser printer, but on the
    relative cost issues involved.

    As far as an absolutely constant data rate goes, I would like to point
    out that $40 of logic on the laser printer side would relieve the NeXT
    of that task.

>Question:  can you print full page graphics on an HP LaserJet with
>no memory?

    No, but it certainly does not require as much memory as you need to run
    postscript.  In fact, memory requirements for postscript are open-ended
    while memory requirements for non-postscript are usually constant.

>>    postscript to a printer when one can spout rasters quickly enough and
>>    that just about removes the processing requirements on the printer
>>    side... And, gee, guess what?  HP's standard printer protocols do just
>>    that... the processing engine in an HP500-C (non-postscript) is no more
>>    complex then the processing engine in NeXT's laser printer.  Less so,
>
>Yes?  Now the HP-500 I know can print characters, decompress bitmaps and do
>all sorts of stuff.  What can the "processing engine" in my NeXT laser printer
>do?  Maybe your HP-500 is different from the ones we have in Germany...

    Processing as in processor.  Your NeXT laser printer could be said to
    not require a processor at all, but that does not mean in any way shape
    or form that printers that DO have processors (e.g. HP500C) have to be
    expensive.	When the processor and memory together cost less then $50
    it's in the noise.  In fact, I would wager that HP is paying less then
    $20 for its processing subsystem.

>Also the data rates and other requirements aren't really comparable for a Laser
>and an ink jet printer.  Remember the thing about apples and oranges?

    Which is why I brought up the fact that a standard parallel port could
    easily be run at a megabyte speeds (almost ethernet speeds.. 8MBits/sec
    verses 10MBits/sec).

>>    in fact.	Not only that, but you lock yourself into NeXT's technology
>>    and must hope that it stays up with the wider world which, as we have
>>    seen, it does not.
>
>Doesn't?

    Is that a grammatical correction? :-)

				    -Matt

>
>Marcel

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    Matthew Dillon		dillon@Overload.Berkeley.CA.US
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