Re: Apple II info please...

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

Supertimer <supertimer@aol.com> wrote:

> 6. ROM:
>      128K in the 1986 "ROM 1" model
>      256K in the 1989 "ROM 3" model (Apple skipped ROM 2
>           so as not to confuse "Apple II" with "ROM 2")

I haven't heard this suggested.  "ROM 2" was skipped to avoid confusion
with Apple's own technical documentation, which used "ROM 2.0" to
describe the second firmware release (ROM 01).  "ROM 3" is the "third
release" as well as version 3.

>      The Apple IIGS also has all the graphics modes found on
>      the Apple IIc.

>         --High Resolution: 280x192 pixels in 6 colors

... with position restrictions.  It is effectively only 140x192 with 6
colours, or 280x192 in monochrome mode.

>         --Double High Resolution: 560x192 pixels in 16 colors.

Ditto.  Effectively 140x192 with 16 colours, 560x192 in monochrome.

>         --Combinations/Variations: 4 lines of text mode can
>           be mixed with a truncated Low Resolution or High
>           Resolution mode graphic.  The text in mixed mode can
>           be either 40 column or 80 column.  Double Low Res
>           and Double High Res modes can't be mixed with text.

Yes they can, but this is rarely (if ever) done.  They can only be mixed
with 80-column text.

I don't think it is possible to mix 80-column text with 40-column lores
graphics, but this is possible (albeit in a limited way) with hires.


It is also worth mentioning that there are two video pages for each of
the 8-bit Apple II modes, but only one video page for Super Hi-Res.

>      The difference between a UniDisk and a IIGS 3.5" drive
>      is that the IIGS drive is controlled directly by the
>      computer while the UniDisk has a separate processor.
>      The UniDisk is thus much slower (up to 4x slower) than
>      a IIGS 3.5" drive.

I usually quote it as half the speed of an Apple 3.5 drive, since the
bit cells are 4 microseconds instead of 2.  There are tradeoffs, however
- the Apple 3.5 Drive requires more complex encoding/decoding (6-and-2),
while the UniDisk only needs bit shifting, and the UniDisk has extra
overhead for command transmission.

>      The SmartPort can support two 800K 3.5" drives, two
>      140K 5.25" drives, and one 100MB CT100 hard drive
>      simultaneously daisy-chained to each other.

Not quite.  It can only physically support four external drives.  There
is a limit of two Apple 3.5 Drives, and/or two 5.25" drives, and/or four
UniDisk 3.5 (or other SmartPort) drives.

> 13. Input/Output:
>      Two RS-232C ports (uses Zilog chip, same as Mac, for
>                         Appletalk and 56.7k serial port max)

They are RS-422/423, not RS-232C.  They can be used with most RS-232
devices, but do not comply with this standard.

>      Composite display output (NTSC or PAL depending on the
>                                country)

I don't think Apple made a PAL version of the IIgs.  Mine (bought in NZ)
is NTSC.  There is a PAL version of the Video Overlay Card.

>      RGB monitor output (Drives an analog RGB monitor.
>                          Besides Apple's, Amiga and Atari ST
>                          monitors work with the right cable)

Note that the scan frequency is 15.75 kHz.  This is too low for most
current multiscan analog RGB monitors.

>      Joystick port

Also an internal game port, which provides the same signals as the
joystick port, plus an additional digital input and four digital
outputs.  This is compatible with the game port in the Apple ][, ][+ and
IIe, except that the IIgs has a fourth digital input (SW3) and is
missing the 0.5 microsecond strobe output.

>      Headphone connector

Stereo, but the internal audio circuitry only produces a mono signal
(paralleled to both channels).  All eight Ensoniq output channels are
mixed together, along with the square wave Apple II audio signal.

>      One Ensoniq sound connector (for input to the ADC for
>           recording samples and access to the raw synthesizer
>           output signals).

The major use of this is to extract a stereo audio signal via a slot
card.  Note that square wave Apple II audio is not available via this
connector.

>      In a twist of irony, you can currently do preemptive
>      multitasking (like Amiga) on the Apple IIGS with the
>      addition of a free product called GNO/ME, providing a
>      UNIX like multitasking kernal under the GUI, much like
>      AmigaDOS...while Macintosh lacks such a capability
>      until Rhapsody is released.

Hardly.  You can run MkLinux now (not to mention other Linux variants),
plus older machines support Apple's old UNIX (A/UX), and there was an
IBM AIX port, mainly used on Apple's server machines.

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand