Apple II

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The computer Apple II (own spelling Apple ][ or Apple //) is one of the first single board computers and micro computers with housing. The company Apple built it from 1977-1993 in different versions. Over 4.86 million Apple-II computers were produced, numerous clones are not counted in. The inventor Steve Wozniak used only simple TTL-ICs and easy to get electronic parts on the main board.The Apple II had seven free slots. They served the modular expansion with plug-in cards (graphic boards, memory expansions, I/O cards, disk controllers, Z80 card, etc.).This idea was picked up and realised by IBM in the PC architecture of today. Also the clever Apple II user could tinker his own cards, if he knew a bit about electronics.


[edit] Miscellaneous

With the Apple II, Apple Computer advanced to the market leader within a short time. This ought to change only with the PC by IBM starting in 1981.

[edit] Buildup

The Apple II is a simple keyboard computer which can be connected to a TV (colour) or monitor (monochrome, mostly green monitors).

It has the following interfaces at the back:

  • Monitor connector (TV connector RF/HF, only over an additionally available modulator or a corresponding plug-in card).
  • Cassette in- and output to connect a conventional cassette recorder (no special datasette, with 1500 Baud).
  • Power connector (rubber connector, the power supply is internal).
  • Starting from Apple IIe: a paddle connector (alternatively also for joysticks; earlier models inside the computer).
  • Processor: MOS Technology 6502 with approx. 1,020484 MHz.
  • Memory: 4 KByte RAM (expandable on the main board to 48, per plug-in card to 64 KByte; in following models up to 16 MByte).
  • ROM: 8 KByte, later 12 KByte on the board; additional ROM possible over plug-in card.
    • Kernel + BASIC (primary version: Integer-BASIC, 8 KByte; then Applesoft-BASIC with Microsoft license, 12 KByte).
  • Graphics: Standard for 40 columns of text and colour (but not both a the same time).
    • Design: (in primary state)
      • Text mode 40 (columns) * 24 (lines) characters, only white on black.
      • HiRes: 140*192 pixel (4 colours: black, green, violett, white; from 2nd version of the main board 6 colours: black, green, orange-red, violett, turquoise-blue, white) or 280*192 (monochrome)
      • LoRes: 40*48 blocks at 15 colours (as HiRes, additionally grey, dark red, dark blue, dark green, brown, pink, bright green, yellow, water blue).
      • Scaleable vector shapes (instead of sprites; needs Applesoft-BASIC or an additional ROM for Integer-BASIC)
  • Sound: built-in speaker, access to address $C030 switches on/off membrane, everything else needs to be done by the software; own sound chip only in the Apple //GS; no sound output over monitor/TV; sound cards available from approx. 1983.
  • Keyboard: 52 keys (QWERTY), in newer models more keys were added.
  • Miscellaneous: Apple-DOS to operate the disk dirve. Unintelligent drive, the DOS runs in the RAM of the computer.

[edit] Overview of memory 64 KByte

    0-  255 ($0000-$00FF)  Zeropage (256 Bytes)
  256-  511 ($0100-$01FF)  Stack (256 Bytes)
  512-  767 ($0200-$02FF)  Keyboard buffer (for 256 characters), also usable for Assembler
  768- 1023 ($0300-$03FF)  free memory  gap 256 Bytes, e.g. for machine language programmes
                           or memory-resident BASIC programmes
 1024- 2047 ($0400-$07FF)  video area for text and LoRes 
 2048-39679 ($0800-$9AFF) free memory for BASIC programmes
   8192-16383 ($2000-$3FFF)  Video range for HiRes
                            (lies in middle of the BASIC range, must be protected correspondingly).
39680-48896 ($9B00-$BFFF)  Apple DOS (tape useable for BASIC programmes)
49152-49297 ($C000-$C07F)  I/O-range (reserved for internal hardware register)
49298-53247 ($C080-$CFFF)  I/O-range (reserved for I/O-cards)
53248-63487 ($D000-$F7FF)  BASIC-ROM  (with Integer BASIC only $E000-$F7FF,
                           $Dxxx then stays unused)
63488-65535 ($F800-$FFFF)  Monitor ROM 

Note: The last 16 KByte RAM of 64 KByte lie parallel to the 12 KByte ROM range, whereby the range $Dxxx is occupied twice.

[edit] Accessories

Over the years there were more and more accessories for the Apple II, both from Apple itself and a series of other suppliers.

[edit] Monitor

As the Apple II could also be connected to a TV with an additional modulator, it was not mandatory to buy a monitor, however, the display was significantly better with a monitor.

There was a 15" green monitor by Apple, which was directly adapted to the design of the Apple II. The speciality was, that the tube could be swivelled up and down some degrees.

[edit] Disk drives

The first disk drives were single drives, which were very chunky, but served their purpose fully.

Later, there was a double disk drive where two drives were built into a very flat housing next to each other. This housing was also adapted to the design of the Apple II. The housing was exactly the same size as the surface above the keyboard of the Apple II. Onto this you could then also place the green monitor with the swivelling tube and had a homogenic looking unit.

In the earlier models, the disk drives were always connected by a plug-in card inside the computer. Only the Apple IIc and the Apple //GS had a built-in disk drive connector, the IIc also had a built-in drive.

[edit] Hard disks

When the first hard drives appeared on the market, the first models were also provided for the Apple II. But as the installed power supply had not enough power, this also had the be exchanged. Therefore the hard disk were most of the time delivered together with a more powerful power supply in one housing.

The first available hard disks had a capability of 10 and 20MBytes. But the purchase was relatively expensive. A 10 MByte hard disk with a more powerful power supply costed as much as about 2.500,- DM.

[edit] Printer

There were several printers for the Apple II, most of them were sold by Apple itself. The Apple models were connected either with the specially provided plug-in card or with a plug-in card with a standard serial RS-232 interface. There were also plug-in cards by other companies (e.g. Epson) with the Centronics parallel port usually used for printers, so that their printers could also be used with the Apple.

Next to the classic 9-pin printers in the size A4 there was also a 9-pin printer for the size A3. It looked like a big box, totally angular and in a fitting design. The printing speed was quite okay, but the vibrations and the noise were enormous and significantly louder than from other manufacturers.

For the Apple there was also the 4-colour drum plotter YEW PL-1000 with the name Apple 410 Color Plotter by the third-party-supplier Yokogawa Electric Works. It could be equipped with special felt-tip pens. As an alternative you could also insert pencils and balls from ball pens. Next to continuous paper you could also use single sheets. This plotter could also be used with the C64, as a comprehensive description of the RS-232 connector and the programme code was enclosed to the manual.

eagle.def Entry
Type     = PenPlotter
Long     = "Yokogawa PL 1000 plotter"
Init     = "IP 0;IW 0,0,380,250; IP 1;\n"
Reset    = "MA 0,0\n"
Width    = 16
Height   = 11
ResX     = 254
ResY     = 254
PenSelect  = "PS %u\n"
PenSpeed   = "PV %1.0f\n"
Move       = "MA %d,%d\n"
Draw       = "DA %d,%d\n"
PenCircleRxCxCy = "AC %d,%d,%d,1800,5400\n"

[edit] Links

WP-W11.png II Wikipedia: Apple II
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