Re: Some upgrading questions...

[dempson@atlantis.actrix.gen.nz (David Empson)]

In article <1995Jan26.000410.83708@kuhub.cc.ukans.edu>,
 <smtrimbl@kuhub.cc.ukans.edu> wrote:
> 
> 1) What is generally preferred, the Turbo IDE DMA card or the RamFast
> SCSI card?  What are the drawbacks to each?

SCSI cards are far more popular.  SCSI hard drives are usually a
little more expensive than IDE drives of the same size, but the
difference is usually less than US$20.

With a SCSI card, you can connect multiple drives (at least seven),
including other types of drives (CD-ROM, floptical, tape drives).  IDE
is usually limited to two hard drive (there are IDE tape drives and
possibly CD-ROM drives, but they are much rarer).

> 2) What sort of hard drives are recommended?  What sort of options
> are there for the Apple II (BTW, I'm thinking in terms of both
> enhanced IIe and IIGS)?  Preferences as to internal/external?  What is
> the general wisdom as to the best systems?

I prefer an external SCSI hard drive, mainly because I can use it on
another computer without having to tear apart the machine.  The hard
drive is much more portable.

> 3) Any opinions/preferences about 3.5 drives, especially HD?  What's
> the best route to go with a HD drive?  (and, yes, I have read the FAQ)

I have the Apple SuperDrive.  If you want to use one of these, you
also need Apple's SuperDrive controller if you want to be able to use
high density and MFM disks.

The SuperDrive can access 400k and 800k Apple (GCR) disks, and 720k
and 1.44MB MFM disks (as used on the PC).  The Mac uses 1.44MB MFM
format for high density disks.

Other options:

- a SCSI Floptical drive (requires a SCSI card), which can access MFM
720k and 1.44MB disks, plus 21MB "floptical" disks.

- a BlueDisk controller and high-density PC 3.5" drive.  This allows
you to use 720k and 1.44MB MFM disks (and 2.88MB extra high density if
you have the right sort of drive).

Note: you cannot access standard Apple 800k disks in either of these
drives.  A low density disk can only be formatted to 720k, and cannot
be read in a standard 800k Apple drive.  Each disk will only be usable
in one type of drive (no two-drive copying, for example).

The BlueDisk is probably the cheapest option of the three.


There are other alternatives, which may be difficult to get:

- Applied Engineering's high density drive.  AE is out of business, so
you can probably only get these second-hand.  They have two versions.

One can be used directly on the IIgs disk port, and supports 400k,
800k and 1.6MB GCR formats.  MFM disks (720k and 1.44MB) are not
supported.  The 1.6MB GCR format is only supported by this drive.  A
special driver may be needed to use this format.

The other type of drive is pretty similar to Apple's SuperDrive, and
supports the same formats (400k, 800k, 720k and 1.44MB).  It requires
a SuperDrive controller in the machine to use 720k and 1.44MB.

- AMR makes a SuperDrive-compatible high density drive.  This requires
the SuperDrive card, and can access 400k, 800k, 720k and 1.44MB disks.

Warning: with the AMR drives (and possible the AE ones), the computer
will lock up if it polls the drive and there is no disk inserted.  You
can unfreeze the computer by inserting a disk.  This doesn't happen
with the drives listed earlier.


IIgs System 6.0.1 includes HFS (Macintosh) and MS-DOS File System
Translators that will work with all of the above drives to read
appropriately formatted Macintosh or PC disks.  You can also write to
Macintosh disks.

There is a set of shareware utilities (written by Peter Watson) that
can write to MS-DOS disks with any of these drives.

> 4) What exactly is an accelerator card?

It is a card that you plug into the computer to make it run software
faster.  There are two brands of accelerator cards for the IIgs: the
TransWarp GS (from Applied Engineering, who are out of business) and
the ZIP GS.

I would strongly recommend the ZIP over the TransWarp, for the
following reasons:

- the company is still in business
- the ZIP is smaller, uses less power and generates less heat than the
TransWarp

The two are pretty similar in operation.  They plug into any slot, and
a cable must be connected from the card to the CPU socket on the
motherboard.  (The CPU must be removed.  The ZIP provides a socket on
the card to hold the original CPU so you don't lose it.)

Both cards have a high-speeed CPU, special hardware to interface to
the computer, and cache memory (8k to 64k for the ZIP, 8k or 32k for
the Transwarp).

They work by caching the contents of memory locations, so that
frequent accesses to the same locations can run at the full speed of
the accelerator (usually 7 MHz to 10 MHz).  If a location is accessed
which is not in the cache, the accelerator has to slow down and read it
normally from the computer (at 1 MHz or 2.6 MHz).  The value is then
stored in the cache in case it is needed again.

I/O operations (screen writes, internal I/O devices and slots) always
run at 1 MHz and are not cached.


I have an 8 MHz ZIP GS in my IIgs.  For most operations, it speeds the
computer up by about a factor of 2.

An accelerator has little effect on disk access speeds (other than
reducing the time required to process the data).  It has a significant
effect on boot times from a hard drive, because a lot of time during
the boot is spent by the computer shuffling data around and setting up
software that has been loaded from disk.


I hope that gives you something to go on.
-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand