ThE STARTiNG
LiNE 
by JohN HARdiE, AC RESOURCE EdiTOR
Some Basic Stuff
This month we'll take a more in-depth look at the different models of classic Ataris out there and discuss their features. But first, let's review some basic concepts about computers in general. I'll start with memory.
A computer's memory is measured in bytes. A byte is equal to one character whether it's a letter, number, punctuation mark, or even an empty space. The word "byte" is four bytes long, one byte for each character. When you say that a computer has 64K memory, you're saying it has 64 Kilo-bytes or 64,000 bytes of memory (remember kilo (K) = 1,000). A computer with 2 megs would have 2 million bytes of memory. This internal memory is called "Random Access Memory" or "RAM"-- don't confuse it with the storage capacity of a disk drive. A disk drive can hold large amounts of program data but can't execute or do anything with it other than to store or retrieve it. A RAM chip can hold the information in it until it loses power (you shut off the computer), or you put new information into it. Another kind of memory is called "Read Only Memory" or "ROM". A ROM chip stores information permanently (when it's manufactured), and thereafter the stored information can be read from the chip over and over. ROM memory is retained even after the power is turned off. A typical example of a ROM chip is a cartridgebased game you plug into your computer, or the operating system chip in the computer itself. If ROM and RAM seem a little confusing, don't worry; you'll get the hang of it after a while. Now that you know a few buzz-words, let's talk computers!
A Million Models?
Not quite, but eight different models of Atari 8-bit computers were released over the years. Let's start at the beginning with the Atari 400:
Atari 400. light brown case with a flip-top lid and membrane keyboard. The power switch, power jack, and I/O connectors are on the right hand side of the unit. The front of the unit has four joystick ports and the back has only the channel 2/3 switch and a builtin RF cable. The computer has 16K of RAM.
One of the main drawbacks of the 400 is its membrane keyboard which is just plain difficult to type on. The small smount of memory prevents it from being used for any serious applications. The machine doesn't have BASIC programming language built-in (not a big deal if you're just interested in playing games). It does have 4 joystick ports in front which means up to 8 people can play the game "Breakout" together. Some companies designed products for the 400 and 800 that used these ports specifically (a drawback for the later machines when ports 3 and 4 were removed). There were also hardware upgrades and modifications for the 400 that brought it up to par with the 800. At least one company designed a regular keyboard as well as upgrading the memory to 48K and adding a monitor output to the machine. However, in its stock form it's best suited for early Atari cartridge games.
The Atari 800
Atari 800: light brown case with a flip-top lid and a regular keyboard. The .power switch, power jack, monitor jack, channel 2/3 switch and I/O connectors are on the right hand side of the unit. The front of the unit has four joystick ports and the back has only the built-in RF cable. The computer has 48K of RAM.
Although similar to the 400, the 800 computer featured two cartridge slots under the lid. However, with the exception of one or two specialized cartridges, the right slot was never used. The flip-top lid itself was removable to reveal four boards (one ROM and three RAM). This access to the ROM and RAM allowed companies to come up with quite a few different RAM upgrades and modifications for the 800. The addition of a monitor jack enabled the 800 to output a better picture using a composite monitor versus a regular TV. The rugged construction of the 800 is legendary: if you want a computer that feels like a tank and is built to withstand a nuclear blast, the 800 is for you.
The 1200XL
Atari 1200XL: white and chocolate brown case with a row of silver keys and three LEDs across the top of the keyboard. The power switch, cartridge slot and two joystick ports are on the left hand side of the unit. The back of the computer has the power jack, monitor jack, RF jack, channel 2/3 switch and I/O port. The computer has 64K of RAM.
Many will argue that the keyboard on the 1200XL is the best one ever built. In addition to the START, SELECT, OPTION, RESET, and HELP keys, the 1200XL also featured four function keys, F1-F4 which controlled various options such as disabling the keyboard or enabling the international character set. The keyboard also has three LEDs labelled POWER, L1 and L2. The L1 and L2 lights were software controllable but were mainly used as part of the built-in diagnostic routine. The programmable HELP key was to allow software companies to provide "one-touch" help screens in their software, although only a few ever used it. The 1200XL only had two joystick ports (a sore spot among multi-player game fans). Internally, as I mentioned before, the 1200 has a built-in self-test routine that checks the computer's ROM, RAM, audio, video and keyboard functions. Also, the 1200 has a current-limiting resistor on the I/0 port which basically prevents anything that draws power from the I/0 port from functioning (like the XM301 modem). Another sore spot for many owners is that in redesigning the Operating System, some of the older 400/800 software was rendered incompatible with the 1200XL (a very short-lived model).
The New XL Computers
Atari went back to the drawing board and soon released the 600XL and 800XL:
Atari 600XL: white and chocolate brown case with a row of silver keys on the right hand side of the keyboard. The power switch, power jack, RF jack, channel 2/3 switch, parallel bus and I/O port are on the back of the unit. The joystick ports are on the right hand side of the unit and the cartridge slot is on the top above the keyboard. The computer has the BASIC programming language built-in and 16K of RAM.
Atari eliminated the four function keys and two LEDs from this and all future models. The (still only two) joystick ports were moved to the right side of the computer. The 600XL has no monitor output and can only be used with a TV (unless you upgrade the video output as described in the December '93 AC). The addition of the parallel bus, or PBI, enabled the user to upgrade the system's memory or add on other future components. The Atari 1064 memory module plugged into the bus and gave the 600XL 64K of memory. Internally the Operating System was slightly more compatible but still required the use of a "translator" disk for older software. Turning the computer on brings up the BASIC language, while holding down the OPTION key when doing so disables the internal BASIC and brings you up in the self-test routines of the machine's Operating System, or OS. Both BASIC and the OS are ROM chips installed on the computer's motherboard.
The 800XL
Atari 800XL: white and chocolate brown case with a row of silver keys on the right hand side of the keyboard. The power switch, power jack, RF jack, monitor jack, channel 2/3 switch, parallel bus and I/O port are on the back of the unit. The joystick ports are on the right hand side of the unit and the cartridge slot is on the top above the keyboard. The computer has the BASIC programming language built-in and 64K of RAM.
There isn't much difference between the 600XL and 800XL other than the physical size of the computer, the amount of memory and the addition of the monitor jack for output to a composite monitor. The 600XL and 800XL both used the same keyboard, which was a planar design. The 800XL was a big seller for several years, even after the XE series machines appeared. This is the most commonly encountered classic-8 machine at garage sales and flea markets. Many earlier units had socketed chips, which has made them valuable for hardware upgrades. Definitely the most popular of the XL series, maybe more numerous than any other Atari 8-bit model.
The XE Machines
Atari's final entries into the 8-bit computer market were basically updated XL models called the 65XE, 130XE and XE Game System (XEGS). For you trivia buffs, the XE stands for "XL-Extended":
Atari 65XE: grey case with START, SELECT, OPTION, etc. keys across the top of the keyboard. The power switch, power jack, RF jack, monitor jack, channel 2/3 switch, cartridge slot and I/O port are on the back of the unit while the joystick ports are on the right hand side. The computer has the BASIC programming language built-in and 64K of RAM.
The 65XE computer is really just a redesigned 800XL in a new style case. Atari dropped the parallel bus from the machine and positioned the cartridge slot in the back. The internal circuitry was changed, but the machine functions much the same as an 800XL. The 65XE and its big brother, the 130XE, are both the same size, and both are slightly smaller and lighter than the 800XL. The XE keyboard is quite different than the XL keyboard, being a sculpted design. Some users feel the XE machines generally have a mushy keyboard and a more flimsy feel, but this is a matter of taste.
The l30XE
Atari 130XE: grey case with START, SELECT, OPTION, etc. keys across the top of the keyboard. The power switch, power jack, RF jack, monitor jack, channel 2/3 switch, cartridge slot, ECI and I/O port are on the back of the unit while the joystick ports are on the right hand side. The computer has the BASIC programming language built-in and 128K of RAM.
Extra memory is the highlight of this model. Essentially a 65XE with enhanced features, the 130XE has an additional 64K of RAM that can be used in programs designed to take advantage of it. The additional memory can also be used to simulate a disk drive (a RAMdisk). Another feature is the addition of the Enhanced Cartridge Interface (ECI) which is functionally similar to and software compatible with the parallel bus on the 600XL and 800XL.
And Finally... A Game Machine???
Atari XE Game System: grey case with pastel colored START, SELECT, OPTION, etc. keys on the main unit. Detachable keyboard. The power switch, power jack, RF jack, composite audio and video jacks, channel 2/3 switch, and I/0 port are on the back of the unit. The cartridge slot is on top of the machine while the joystick ports are on the side. The computer has the BASIC programming language and Missile Command game built-in and 64K of RAM.
Atari chose a new approach with their final entry into the 8-bit market by calling it a game system. The idea was that customers could go at their own pace with the machine. While great for playing games, the user would discover they already had a computer if they decided to upgrade. Pretty much a 65XE in a redesigned case, the XEGS also boasted the game "Missile Command" built-in, as well as the BASIC language. The unit was packaged with a light gun as well as the "Bug Hunt" and "Flight Simulator" cartridges. Unfortunately for Atari, the system never took off (pun intended).
Time To Move On
So there you have it: the major models of Atari 8-bit computers in a nutshell. There were a few others, rarities which never made it to mass production. In a future column we'll take a closer look at Atari-made and Atari-compatible disk drives, but that will depend on whether this magazine survives.
Hope to see you next time!
