| This was in last nights stuff. Sounds like a really cheap way of
doing it. (now to come up with the $195 (Canadian))
Newsgroups: comp.sys.amiga
Path: decwrl!labrea!aurora!ames!think!bloom-beacon!mit-eddie!uw-beaver!ubc-vision!van-bc!root
Subject: WEDGE answers
Posted: 11 Nov 87 03:23:28 GMT
Organization:
[<<<<<<<<<<<<<<<<<<<<<<<<<<<<< line eater food >>>>>>>>>>>>>>>>>>>>>>>>>>>>>]
WHILE THIS POSTING IS NOT COMMERCIAL IN NATURE (AT LEAST NOT IN MY
OPINION) SOME PEOPLE MAY BE OFFENDED BY RESPONSES TO QUESTIONS REGARDING AN
EARLIER POSTING ABOUT INEXPENSIVE HARD DISKS FOR THE AMIGA. NOW IS YOUR
CHANCE TO HIT THE 'N' KEY...
in <15397@watmath.waterloo.edu> Fred Walter writes:
> What exactly is The WEDGE ? If you are going to be commercial, at least
> fully describe the product.
Hello.
Dave Allen (the poster of the announcement) asked me to reply to your
questions - and since I thought that your questions may be of general
interest, I am posting my reply to comp.sys.amiga. Please feel free to
re-post this message, but please note that I am not involved with Reiter
Software in any position. I did not design the WEDGE - Jim Brooks did, and I
have nothing to do with the marketing/sale/etc. of it. That out of the way,
I did write a significant portion of the driver software, and I am an early
owner of the Wedge - I point-to-point wired a prototype for my use.
The WEDGE is a small printed circuit board that plugs into the 86 pin
expanion socket on the side of an Amiga 500 or an Amiga 1000. [Larry
Phillips of CI$ fame is trying to make an Amiga 2000 version of the WEDGE] It
does not auto-configure, and must be MOUNT-ed. Into the WEDGE plugs a small
backplane which has one empty PC/XT style slot, to be used for a standard PC
hard disk controller. A backplane with more than one empty slot would allow
more than one PC hard disk controller to be plugged in, and more hard drives
to be on-line with the proper drivers. A WX1 controller can control two
drives, each of which may have 1024 cylinders, 16 heads, and 64 sectors [I am
typing this from memory - so excuse any silly mistakes.] Therefore,
theoretically you could have two 500Mb ST506 drives with one controller.
Since most people have smaller drives than the theoretical maximum, smaller
drives will work :-) :-) :-)
> I would presume it is a slap on the side something or other that allows you
> to use IBM hard drive controllers so that one can use an inexpensive IBM
> hard drive. Is this what it is ?
That is entirely correct. The current driver software works with the
Western Digital WX1 controller, and should work with some other controllers,
if they are fully compatible to the WX1 [i.e. same registers, same DRQ
handling, etc]. Some other controllers have been tried - and Jim [the guy
who designed the hardware and did the initial driver] is trying to get more
cards to work. But the WX1 works quite well - I am using a WX1 controller
with an old full height 10Mb Tandon. Basically you need the WEDGE, a WX1 (or
compatible) PC/XT controller, an ST506 hard drive, case and power supply for
the drive. Dave is selling both the WEDGE and a couple of different
complete packages, including 20Mb or 40Mb drives.
> Does it pass the buss properly ? (IE. can I use my 2 meg slap on the side
> expansion ?)
The WEDGE does not pass the bus due to the possibility of overloading the
bus and possible timing problems. However, if your memory expansion board
passes the bus, the WEDGE may be able to work plugged into it. I have an
Insider installed in my Amiga [1Mb internal] and it works fine with that. If
your memory board passes the bus, then send me e-mail telling me the make &
model, and I'll ask Jim to see if he can try it out - as there is a large
local Amiga user's group, someone is likely to have the same model memory
board as you. Ofcourse I cannot gurantee that he can find such a board here
or that he can try it out, but I could certainly ask [he is currently trying
a memory board/WEDGE combination out for another club member]. Since he is
not on the net, if you have questions for Jim, you can send them either to me
or to Dave Allen - and I'd be happy to answer further questions too, if you
have more.
> I presume it comes with a proper software driver ? Source would be nice
> (so it can be tweaked to go faster, etc.) ?
The board [or package deal] does indeed come with the proper driver. As
to whether the source is to be made available, I'd have to ask Jim - but my
guess is that it will not be made available [but don't quote me on that :-)]
As far as tweaking it to go faster, your's truly is working on that. I have
already managed to increase the speed by about 30% over the original figures.
> How does one of the hard drive systems described in the previous article
> compare speed-wise for program loading/saving/etc. to the other hard drives
> available ? (I think a program to check this info is on one of the fish
> disks .. I remember seeing a whole bunch of stats for other AMIGA hard
> drives posted a while back).
The program you are thinking of is DiskPerf. Currently, with my latest
speed-ups at an interleave of three the driver is reading at about 34k/sec
and writing at about 22k/sec, about 60 directory entries/sec [these figures
are off the top of my head - the hour is late and I could not find the
figures I wrote down - but they should be pretty close]. The bottleneck at
this point seems to be the Amiga's file-system - the reason I say that with
fair confidence is that the latest driver implements pre-fetching and a small
cache [small yes, but with a 65% cache hit ratio with only 16 buffers!] and
Jim has put a scope on the disk controller, and AmigaDOS is spending about
60ms between accessing the disk [as most requests are satisfied from the
prefetched and/or cached data]. The much-rumoured new file-system should
speed up the drive considerably. As for the ranking, as I recall the Pal-Jr.
DMA drive was faster for reading by about 6k or so [If I recall, it clocks in
about 40k or so per sec], but the WEDGE+WX1 controller was faster than most
non-DMA drives that appeared in that Amazing Computing article. I am still
trying to squeeze more performance out of the driver.
> Does anybody out there have one that can give a review ?
I have a prototype of it [far more primitive than the finished product -
but it works!] and I have been quite satisfied with it. I have had it
running for over two months without any problems, and Jim has been extremely
helpful in getting my hand-wired prototype to work [and he was very kind in
letting me build a prototype of his design, and trouble-shooting some wiring
mistakes of mine]. It works - what can I say? My startup-sequence used to
take about four minutes to crunch through, but now it finishes in about 40
seconds. My machine is far more usefull now - I do not waste a megabyte as a
ram disk. It is not as fast as a DMA drive, but it is by far the cheapest
method of getting a hard disk for the Amiga. When the new file-system shows
up [I hope soon!] the throughput should greatly increase [I recall reading
rumours on comp.sys.amiga claiming 3x-5x improvement in speed with the new
file-system - but I have no way to verify such claims :-( ] The WEDGE + WX1 +
hard drive is currently about 3x the speed of the floppy [but much less
trashing due to the pre-fetching & caching] but the perceived speed increase
is greater. I can double-click on VT100 (thanks DBW!) and it is up & running
in less than two seconds [about 1.5s]. Incidentally - 10Mb is too small a
drive for an Amiga [but 10Mb is a heck of a lot better than 0Mb!].
> Since the local dealer has 20 meg hard drives (I forget the make) for
> around $1500(?) cdn, I would like to know more about The WEDGE.
If you have any more questions, please e-mail me. I agree - current hard
drive prices for the Amiga are too high [with the exception of the WEDGE 8-)
] - this is what prompted Jim to make the WEDGE. Sorry I could not provide
more exact DiskPerf figures right now - if you wish I could run diskperf and
re-direct the output to a file and mail it to you - I keep trying to improve
the driver, so a somewhat higher speed is not out of the question [even
though I am certain I am getting pretty close to the AmigaDOS limit - I know
that VD0: (thanks Perry! - I sent in my $10...) gets higher rates, but VD0:
does not need to do the SLOW seeks. <FLAME ON> The problem lies in the way
AmigaDOS insists on seeking all over the place for things... among other
problems <FLAME OFF>. Why couldn't the file-system use a nice elevator
algorithm? At least the file system is robust and has lots of redundant
links allowing easy recovery (thanks for DiskSalv Dave Haynie!).
Anyway, I personally believe that Dave Allen & Reiter Software are
offering a VERY good deal - however, owning a WEDGE and working on its
software may have biased me a bit (naahh...).
DISCLAIMER:
I am not employed by any of: Dave Allen, Jim Brooks or Reiter Software
and nothing I've said above is to be construed as the opinion of the Dave
Allen or Jim Brooks or Reiter Software.
[as a matter of fact, I am a currently unemployed Computer Science student]
p.s.
Thanks to the Amiga development folks for bringing us the Amiga family,
and to the diligent folks at CATS for answering questions on the net and
putting up with the periodic flaming they receive [undeservedly, in my
opinion. Now as for the marketing types... 8-) ]
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