Apple IIgs

In September 1986, the Apple IIGS was introduced as the successor to the Apple IIe. It was the fifth and last model of the Apple II series, when the Apple / / c , only a faster, offered only in the U.S. Apple / / c, does not count. The Apple IIGS was the last computer, the Apple co-founder and father of the Apple II series, Steve Wozniak had designed for Apple before its active engineering activity ended in February 1985 at Apple ( he remained an employee with a nominal salary, took but for Apple, only PR - tasks ).

The "GS" is short for. "Graphics " and "Sound ". The Apple IIGS was a hybrid machine, on the one hand was able to use the software and hardware of the Apple II series and on the other side (but not in time for launch ) a similar graphical user interface as brought back from the Apple Macintosh. In contrast to the black-and- white representation of the Macintoshes of the time a colored GUI was here first bid on an Apple computer; However, the former Macs had a higher vertical resolution and were significantly faster.

History

The IIGS had compared to all previous computers of the Apple II series is a true 16 -bit architecture, a higher clock frequency, direct access to several megabytes of memory, a new design, a support of 3.5 -inch floppy disk drives with more storage and a mouse as standard equipment (extra cost for Apple IIe / IIc 300 DM). Keyboard and mouse were connected via the new Apple Desktop Bus (ADB ), which is considered one of the technical ancestors of the Universal Serial Bus.

Apple had at that time a competitive product price and performance against the Atari ST and the Commodore Amiga ( the IBM PC had at that time no significant common graphical user interface ) on the market, without compromising the high-priced Apple Macintosh.

For users who want to apply any old 8 -bit software, but only new 16 -bit software, was the price / performance ratio of the Apple IIGS in comparison to its direct competitors, Atari ST and Commodore Amiga significantly worse - the Apple offered less speed and less graphics acceleration options for games at a higher price, so that then also much less games for the system appeared. Only on the side scenes quality of workmanship, quality of documentation and compatibility with existing software was superior to its competitors, the Apple. Only later could be made ​​good ground with the delayed finished Operating System GS / OS to another area because this was far more stable than the existing at the same time competing products.

At that time there were at Apple internally so much controversy that both founders finished their active participation, Steve Jobs left the company even completely. The " vernacular" was of the opinion that Apple has so himself thrown out of the market, since Apple is not the right people have steered the company. The Apple IIGS was barely developed - it was published in 1989 a " ROM 3 " referred to various errors adjusted version with more firmly built-in memory and slightly improved operating system, but offered no speed increase and no real new features - the company has fully concentrated on Macintosh concentrated. The Apple II line was produced until 1992.

Specifications

Main processor

The main processor was a 16-Bit-65816/65C816-Prozessor of Western Design Center (WDC ), who could make a software compatibility for 8-Bit-6502/65C02 of MOS Technology of the Apple II / IIe / IIc. A software switch in the processor decided whether the processor was running in 8- bit emulation mode ( emulation mode) or in 16- bit mode (native mode). In 8- bit mode he was using the same commands as an Apple II / IIe / IIc are addressed and ran with it with the software (with the choice between the two speeds 1 and 2.8 MHz ), but also with the same memory limit 64 KiB of address space ( emulated 16- bit address bus ), which could be circumvented only indirectly through bank switching. The processor is still manufactured today.

The number " 65 " in the product of the WDC 65816/65C816 refers to the compatibility with the 6502/65C02 of MOS Technology. The number " 816 " means that the processor is in the 8 - and 16 -bit mode can operate. The processor can in 16- bit mode ( 24- bit address bus ) address a maximum of 16 MiB of RAM. However, hardware limitations prevent the IIGS memory expansion over 8.25 MiB addition ( the later model 9.125 MiB).

Memory - RAM

The IIGS 1986 had 256 KiB RAM, the model 1989 was 1.125 MiB. The RAM was divided into each 128 KiB (4 each chip ) " fast" and "slow" RAM. The " faster " memory is only used for programs. The " slower " memory, which corresponded to the memory of the Apple IIe was for screen output, I / O processing and used as system memory. In the 1989 model, there were still 128 KiB slow memory, but 1 MiB fast. For 16 -bit programs were at 256 KiB RAM maximum 176 KiB RAM available (128 KiB RAM faster system memory, depending on resolution and equipment (expansion cards) ). The RAM was due to expansion cards to a maximum of 8.25 MiB ( 1989er model: 9.125 MiB) be expanded, with extensions beyond the maximum officially supported by Apple 4.25 or 5.125 MiB changes in the operating system require. The upgrades increase only the "fast" memory, the "slow" always remains at 128 KiB.

Almost all IIGS - specific programs, including all but the earliest versions of the GS / OS operating system, require a memory configuration of a total of at least 1 MiB. On the 1986 model can be no memory expansion card almost only the conventional 8 -bit programs the Apple IIe / IIc use. From 4 MiB virtually all existing programs run correctly, a memory expansion beyond this then serves only to reduce the frequency and duration of drive access.

Memory - ROM

The IIGS had 128 KiB ROM ( 1986 model) or 256 KiB ROM ( the 1989 model). The ROM could be expanded using expansion cards to a maximum of 1.125 MiB or 1.25 MiB, of which but little use has been made.

Sound

The Apple IIGS had - unlike its predecessors, which only an even simpler version of the PC system speaker offered no additional sound cards - on the motherboard an Ensoniq 5503 -DOC (digital oscillator chip) sound chip from the developer of the MOS Technology SID, as it for example, the synthesizer manufacturer " Mirage Music " used. This chip had to save one 's own memory of 64 KiB digital music and edit. The chip had a digital -to-analog converter 32 and oscillators, Apple used by those in the firmware of the IIGS two for internal purposes. The rest were used for the tone, either as 15 stereo voices or 30 mono voices. Further, the chip has been able to generate sounds over the so-called wavetable synthesis. For this purpose, two digital -to-analog converter ( DAC - Digital Analog Converter ) were present that had a resolution of 8 bit and was able to access an internal 64 KiB wavetable memory. Thus, the Ensoniq 5503 was able, like the then largest competitor Commodore Amiga to produce digital stereo sound. Apple, however, limited the sound output by only a mono connector for headphones / speakers was installed. With the help of an additional ( passive ) expansion card stereo output signal could be obtained.

Apple Corps, the rights company of the Beatles strained, because this sound options a lawsuit against Apple Computer, since they violated by their view contrary to the agreement between the two companies that Apple computers the name " Apple " was only allowed to wear as long as they are not in the music business were engaged. As a consequence built Apple computer after many years in the Macintosh models no dedicated sound chips more.

Graphic

The integrated graphics chip had a 12-bit color palette ( 4096 colors) and could, in addition to the video modes for the Apple IIe Show the following additional modes:

• 320 × 200 with 16 colors
• 320 × 200 with 16 color palettes of 16 colors: Here each image line could be provided with a different color palette. This allowed a representation of theoretically 256 colors.
• 320 × 200 with 200 color palettes of 16 colors: Here each image line could be provided with a color palette, which is a representation of theoretically 3200 colors allowed.
• 320 × 200 with 200 color palettes, each with 15 colors a fill color:
• 640 × 200 in four colors: This mode is only used for menu operations and for the Apple logo.
• 640 × 200 in 16 simulated colors: Here was simulated by means of two color palettes of four colors, each used in a different area, a display of 16 colors. This mode was the mode for office programs. Such modes at that time were quite common.