toadmonkey wrote:
> What's the difference between the Apple ][c, the Aplle ][+ and the
> Apple 2 you guys talk about?
You could try reading the FAQs for this group, but as I'm here
already...
The "Apple ][" was the original model, released in 1977. It had a 6502
processor running at about 1 MHz. It went through several minor
hardware revisions over the next year or two. It is a desktop machine
with built-in keyboard and power supply, support for 4 KB to 48 KB of
RAM (minimum of 12 KB installed, if I remember right), with eight slots
for expansion cards, composite video output, a game connector for
paddles/joystick, and casette input and output for data storage on audio
casettes. (You can add a disk controller card, and a 16 KB memory
expansion card became a standard feature a few years later, for a
maximum of 64 KB of RAM.)
The keyboard is somewhat limited - no support for lower case characters
and some of the more obscure ASCII symbols. Lower case also cannot be
displayed on the text screen (unless you replace the character generator
ROM).
The video display modes are: 40x24 text, 40x48 lo-res graphics (16
colours) and 280x192 (monochrome) or 140x192 (colour) hi-res graphics
(six colours with limited placement). There is also a mixed mode which
has four lines of text at the bottom of the screen in conjunction with
40 rows of lo-res graphics or 160 lines of hi-res graphics.
A wide variety of expansion cards were available from Apple and third
parties. Popular cards of this era included parallel and serial
interfaces for printers and modems, 80-column text display cards, and
the disk controller card.
The "Apple ][+" was an improved version, released in 1978. The main
functional change was a new version of the system monitor firmware which
supported automatic startup from floppy disk, and a switch from Apple's
own "Integer BASIC" (written by Steve Wozniak) to "AppleSoft BASIC",
which was written by Microsoft; it added floating point support. There
were several minor hardware enhancements, most of which were available
in later motherboard revisions for the Apple ][. The motherboard
revisions around the time of the ][+ release had dropped support for 4
KB RAM rows, so the supported RAM capacities were 16 KB, 32 KB or 48 KB
(plus the 16 KB memory expansion card, still an option at this time).
It is possible to convert an Apple ][ into a ][+ (or vice versa) by
swapping the ROMs, motherboard features notwithstanding. The I/O
functionality is identical. Apple also had a ROM card which allowed
both sets of ROMs to be installed in one machine, with a switch to
select which set was active at startup.
The ][+ keyboard and display have the same limitations as the ][.
In 1982, the "Apple //e" was released. This machine is in the same
general style and shape as the ][ and ][+, but has many improved
features:
- 64 KB memory is included as standard (building the 16 KB memory
expansion card into the motherboard, eliminating one of the slots).
- The keyboard and text display add support for lower case and the full
ASCII character set.
- An auxiliary slot was added, providing support for an additional 64 KB
of RAM, which is accessed through bank-switching techniques.
(Third-party cards extended this to at least 3 MB by providing multiple
banks.)
- The motherboard has built-in support for 80-column text display,
requiring a 1 KB or 64 KB expansion card to be installed in the
auxiliary slot.
- An alternate character set is available, replacing flashing characters
with a full complement of inverse characters.
- An external game connector was added.
- International models of the //e have a switch to select between US
English and the local language, affecting both the keyboard and text
display.
- Revision B of the //e added a "double hi-res" graphics mode (560x192
in monochrome, or 140x192 with 16 colours, again with limited
placement). This mode requires a 64 KB (or larger) card in the
auxiliary slot.
Apart from these changes, the original //e was functionally identical to
the ][+.
The "Apple //c" was released in 1984. It is a smaller semi-portable
machine, with built-in peripherals instead of the slots of the //e. It
has a 65C02 processor (which adds a few more instructions) and 128 KB of
RAM (the equivalent of a //e with 64 KB card in the auxiliary slot).
The built-in peripherals are a 5.25" disk drive, a disk port for
connecting an external drive, two serial ports, support for a mouse, and
audio output (with volume control). The cassette input/output was
eliminated. There is also a video expansion port which can be used to
connect an LCD display, or can be used with an external adaptor to drive
an RGB monitor. The power supply is split in two: an external "brick"
which deals with the mains, and an internal power converter. The
"brick" produces 18VDC, but the IIc's power converter is capable of
running from a DC power source as low as 9V (e.g. a 12V car battery).
There was a later revision of the //e (the "enhanced //e") to bring it
in line with some of the improvements made in the //c (e.g. support for
entering Applesoft BASIC commands in lower case, the "MouseText"
characters, and the use of a 65C02 microprocessor instead of a 6502).
This was available as a simple four chip upgrade for older //e models.
The final revision of the //e changed the appearance of the case
("platinum IIe"), adding a numeric keypad to the keyboard. It was
otherwise identical in functionality to the enhanced //e.
The //c also had enhancements, adding support for an external 3.5" drive
(a simple firmware update) and a 1 MB memory expansion card (new
motherboard required).
In 1986, the "Apple IIgs" was released. This was a radically improved
model, using a 65816 processor, which is able to operate in a native
16-bit mode as well as emulate a 6502 or 65C02 in 8-bit mode. The CPU
can be set to run at 2.8 MHz, or slowed down to 1 MHz for compatibility
with old software.
The IIgs inherited several features from the Macintosh, including
standardisation on the 800K floppy drive and support for the AppleTalk
(LocalTalk) network. The IIgs was the first machine to use the Apple
Desktop Bus (for connecting the keyboard and mouse).
The IIgs is a desktop machine with a separate keyboard. It has slots,
like the IIe (seven standard slots plus a memory expansion slot), and
also has built-in peripherals, like the IIc (but no built-in floppy
drive). Most of the built-in peripherals use the same memory area as a
particular slot, preventing the simultaneous use of the slot and
corresponding peripheral (except with some types of card).
The IIgs's built-in peripherals are two Mac-like serial ports, mouse
support, disk port, game port, RGB video output, composite video output,
audio output, and a real time clock.
The original release of the IIgs has 256 KB of RAM, which can be
expanded to a maximum of 8.125 MB via the memory expansion slot. There
was a revised model in 1989 which has 1.125 MB of RAM built in (with the
same expansion limit).
The IIgs supports all the video modes of earlier models, and adds a
"super hi-res graphics" mode, which supports 320x200 or 640x200 with 16
colours selected from a palette of 4096 (limited placement in 640 mode,
effectively restricting you to four colours per line unless "dithering"
techniques are used).
The IIgs also has signifcantly improved sound hardware, based on the
Ensoniq DOC, which can support 16 channels of audio output and some
pretty advanced features. (The built-in audio output is mono, but you
can add cards which provide stereo or multi-channel output.)
When running in emulation mode, the IIgs supports nearly all software
from the 8-bit Apple II models.
When running in native mode, the IIgs supports a desktop environment
which is very similar to the Macintosh, complete with a Mac-like toolbox
which provides standardised user interface support to applications.
The final model worth mentioning is the Apple IIc+, which was released
in 1988. It is basically an Apple //c with a built-in 3.5" drive
instead of a 5.25" drive, and it has a 4 MHz accelerator.
Apple discontinued the Apple II family in 1993.
The Apple IIe is the most common model by far: I've seen estimates of 6
million machines sold, compared to about 1 million for the IIgs, with
similar numbers for the ][ and ][+ lumped together; I don't recall the
nominal figure for the IIc, but I expect it was lower.
--
David Empson
dempson@actrix.gen.nz