Conference hydra::amiga_v1

do a NOTES> DIR/TITLE="hard" and you'll probably find what you need.

John

    Or better yet, go pick up a copy of AMIGA WORLD or Amazing Computing.
     They've started carrying adds for A500 hard disks.   The cheapest
    I've seen are Pioneer Computing (< $600 for a 20-meg up to $949
    for a 65-meg) and some place called Computer Mart ( $849 for a 65-meg.)
    Both of these units come with case, power supply, controller's,
    etc... 'everything you need to hook it up and go' so they say.
    However, neither of these have the place for the expansion ram.
    
    I've finally convinced my wife that the world will end if I don't
    get a hard disk soon, so I've been looking around at what's available.
     The more I think about it, the more I think I'm gonna pay a little
    extra for a good drive with the slots for expansion ram.  I'll want
    more memory when it gets cheaper.
    
    BTW, one of my 'minimum requirements' was that the drive be real
    SCSI... the murmurings (sp?) I hear around here say that real SCSI
    is faster and better.  
    
    Also, one question for the general board of gurus.  I'm sort of
    holding off buying my harddisk until after Christmas in the hopes
    that the prices will drop.  (You know, after the holidays type sales.)
    Does this make sense with something so non-ordinary as a hard drive
    for a personal computer?
    
    
    					John

    Memory Location in Wellesley recommends GVP (Great Valley Products?)
    for just such an expansion.  A500, 20 to 50 MB disk, 0, 1 or 2 MB memory.
    They're available mail-order, but I can't remember the price (seems
    to me that they were >$600 for 20 MB).                      
    
    <<Tim>>

For those willing to do a little work collecting the pieces....

  o A  C-Ltd  controller  can  be had for $250 - list. Less than $200
    mail order.

  o Seagate  ST277 (65 meg 40ms SCSI half height disk) can be had for
    $390  (what  I paid at a recent computer flea market - new!). Can
    be seen in Computer shopper for less than $440.

  o A  case  with  power  supply  can be easily had for under $100. I
    bought  a  baby  AT  case  with  power  supply  for $75. Room for
    mounting a 5.25 HH floppy, plus 5 ST277 disks. This only provides
    325 meg of hard disk.

  o A 50 conductor ribbon cable (4 ft should be more than enough) and
    2 50 conductor header connectors. Assembly requires only a vice.

    The  total  cost  for  a  65  meg  disk system that diskperf's at
238k/sec for an A500 is only $675 to $800 depending  on  how  good  a
shopper you are. The A500 does have a 68010, that upgrade cost me $14
and  it  is  not  clear  what  affect that has on the diskperf quoted
above.

    So,  as one can see a disk system for an A500 can be put together
for quite a bit less than a comparable packaged system and provide  a
lot  of flexibility. Mine has worked with as many as 5 disks at once.
Works fine, lasts a long time...

	-SES

    Re: .-1
    
    You said a 4 ft. ribbon cable?  Wait a minute...  You mean you can
    have a 4 ft. ribbon cable between your expansion door on the side
    of the A500 and whatever you're hooking it to?  I've been wondering
    why all of the A500 add-ons I see have to sit snug up against the
    left side of the keyboard.  One of the local hardware guys says 
    it's probably due to the noise and interference problems you get 
    with longer ribbon cables.  I'd be quite happy to hear that add-ons
    can be placed behind my keyboard instead of right there where I
    usually put my drink and sandwich.  :-)
    
    
    					John

    re: .5
    
    That's 4 ft. of SCSI 50pin ribbon cable, not an expansion bus extender.
    
    -dave

Yup. The SCSI cable can be (ala ANSI) 6 meters long (about 18 feet). I won't go 
into the details, but it may or may not work *well* at 6 meters depending
on your configuration/environment.

As far as the A500 expansion bus. Thats the Microprocessor bus, right? Meaning
the 68000 "pins" head out the side (among others).  Can you imagine having
4 feet of PC board etch hanging off the 68000?  :-)


John

    D*MN!  This means that after I get my Hard Disk, I'll starve to
    death... won't be able to eat while I work anymore.  :-(
    
    BTW, how do the SubSystem 500 type expansion boxes deal with this
    problem.  From what I hear, they have a bus pass-thru.  That's about
    2 feet.  
    
    					John

I don't know. They probably have bus trancievers in thier box.

John

Re: .8

>    BTW, how do the SubSystem 500 type expansion boxes deal with this
>    problem.  From what I hear, they have a bus pass-thru.  That's about
>    2 feet.  

Poorly.  Actually, I have no experience with the SubSystem, so it may
do a better job of it.  However, any old timer can tell you about all
the folks that tried and failed to put two "slap on the side" expansion
boxes on their 1000.

In the original Zorro design, Commodore stated that in general, you
could hang one expansion device (a box of slots counts as only one
device) off the bus connector.  But if you were real careful and
buffered the bus pass through, you might be able to hang two devices
off the bus.

In the bad old 1000 days, most (all?) of the expansion devices with bus
pass thorough didn't bother to buffer the bus.  About half of the people
who had two slap on the side devices got them to work together.  About
the other half have terrible problems (which they attempted to solve
by replacing PALs, grounding random parts of the motherboard, using
a ceramic packaged 68000, ...).

People also circulated lists of "compatible" expansion products ("a
friend of mine was able to use a C LTD controller with a Starboard,
but you had to plug the disk controller in first...").

As you've gathered, I don't consider bus pass through to be a very
robust expansion strategy.

By the way, Zorro was the code name for the expansion box for the 1000
designed by Commodore.  Commodore never built it (probably due to their
financial problems at the time), but did sell the plans for the box
to anyone with $20.  Thus, plug in cards for the Amiga are called
"Zorro cards."