Atari vs. Apple drives, which can both be driven from a single expansion card in the
Apple II. The machines that emerged as the
Atari 8-bit computers had originally been designed as part of a project to develop a driver
chipset for a new
games console. During the time the chips were being developed, the
Apple II became very popular and propelled
Apple Computer into one of the largest
initial public offerings of its era. Atari, recently purchased by
Warner Communications, had placed
Ray Kassar in the CEO position in March 1978. He decided to redirect the chipset to the emerging
home computer market to take on Apple. One of the key reasons for the
Apple II's success was the
Disk II, introduced in June 1978 at the very low (for the era) price of $495 () plus the interface card. The interface was based on a system
Steve Wozniak had previously built while working at
Hewlett-Packard to control a
Shugart Associates SA-400 floppy drive.
Steve Jobs went to Shugart and asked for a stripped-down drive mechanism for $100; Shugart responded by shipping them 25 prototypes of a new model they called the SA-390. Woz's controller then provided the bits that Shugart had removed, allowing two drives to be controlled by a single card. The resulting system operated at 15 kbps, making it faster than any of the competing designs of the era.
New design The new Atari machines faced the problem that the
Federal Communications Commission (FCC) had recently introduced standards to deal with the profusion of systems that connected to televisions that were causing significant problems with interference. The new rules were extremely strict, requiring a lengthy and costly testing suite to be run against any new product and anything that connected to it. Apple avoided this by not connecting to a television; instead, a 3rd party sold the required
RF modulator and thus Apple didn't need testing. Atari was determined to make a plug-and-play system that connected directly to the television, like the
Atari VCS. This precluded the idea of having
expansion slots that could be connected to external equipment, like on the Apple, as the openings would be difficult to shield property to avoid RF leakage. This led to the introduction of the
SIO serial bus, a system that allowed devices to be
daisy chained to a single port. Using a cable made shielding to the required levels much easier, but also required the external devices to host the interface circuitry that would normally be placed on an
expansion card inside the machine. This drove up the complexity and cost of the external devices. To offset this as much as possible, Atari used discarded
MOS 6507 chips from the VCS production line as the basis for the interface. Atari purchased large numbers of 6507s from
Synertek that were officially rated for operation at 1
MHz, but most of them were being able to run at a slightly higher 1.1 MHz that the VCS worked at. Those that did not, a small proportion of the chips, were simply warehoused at Atari. As they had already been paid for, and were essentially free, they were perfect for use as low-cost
microcontrollers like the one in the 810. Atari's drives entered the market almost two years later than Apple, giving them time to take advantage of the rapid improvements taking place in the industry. Most notable was the entry of several other manufacturers to the drive market, including
Alps Electric and
Micro Peripherals Inc (MPI). Atari arranged a deal with MPI for their mechanisms and designed their own controller to drive it, combining the 6507 running at 500 kHz with a standard
FM encoding drive controller, the
Western Digital FD1771. Despite these efforts to lower cost, the resulting drive was still more expensive than the Disk II, listed at $599 when it was introduced in 1979. It also had the disadvantage of running slower than the Disk II; although the underlying SIO bus was running at 19.2 kbps, the effective data rate was generally around 6 kbps, compared to about 15 kbps for the Disk II. This is one reason the machine was never considered seriously in the business market; applications like
VisiCalc were not competitive with the Apple II when run on the Atari or
Commodore 64. In a 1982 review for a third party replacement,
InfoWorld described the 810 as "noisy, slow and inefficient by today's standards, and it had some reliability problems" and then described the sounds as "At times it almost seemed sick, the groans and creaks were so intense."
Brian Moriarty, writing in the
ANALOG Computing magazine, described it as having "notoriously poor speed regulation" in maintaining its non-standard 288 RPM, while Garry Francis noted in
Page 6 magazine that the speed would tend to drift over time, causing disks written at different speeds to become unreadable without adjustment. This led to a number of small programs, like Snail and Drive RPM, that would test the speed of the drive in software in order to aid the user in adjusting it back to 288. Initial units shipped with
Atari DOS 1.0, sometimes known as DOS I. This was replaced by DOS 2.0S in 1981.
815 While the 8-bit machines were first being introduced, the first
MFM double-density drive controllers were appearing, allowing the same disks to store twice as much data, 180 kB. Early advertising for the new machines often showed the
815, which combined two drives in a single case and used MFM encoding. The price was listed at $1,495. For reasons unknown, the 815 was never produced in quantity. Small numbers were hand-built using
Tandon drives during 1980 and a few shipped to customers starting in June, but full-scale production never began. It continued to appear on company price lists for the next year, with the last known reference being Atari's internal price list of 24 August 1981. To support the larger storage capacity, the drives used a modified version of DOS 2.0, 2.0D. The controller was custom and only supported MFM, making the 815 incompatible with disks used in the 810.
Third party upgrades Third parties exploring the capabilities of the 810 system soon demonstrated that the 19.2 kbps speed of the SIO communications could be easily doubled. It was later revealed that the speed was not a limitation of the SIO port, but the maximum speed of the
logic analyzer available in the lab where it was being developed. Best known among the many products was the
Happy 810, introduced in 1982. It added a buffer able to cache one entire track of data, and along with the associated Warp Speed software, increased read performance about three times, making it very competitive with the Apple II. The performance and reliability problems with the 810 also led to a thriving market for third-party drives like the Rana 1000 and
Indus GT, along with a wide selection of replacements for Atari DOS. Combining one of these drives with a replacement DOS offered higher performance and often true double-density support. As the double-density format had been set with the 815 in 1980, these drives used that format as the basis for their disks as well.
Replacement In April 1982, Atari began the process of designing improved versions of the 8-bit series, then referred to as the Sweet 8 and Sweet 16. Changes to the plans led to only one of these designs being released as the 1200XL. Containing "no true innovations", the most notable change was the introduction of a new
design language from Regan Cheng using off-white and black plastics with brushed metal overlay on switches and other fixtures. This led to the introduction of a new line of peripherals that matched the styling. Initially this included the
Atari 1010 cassette deck, the
Atari 1020 plotter, and 1025 printers. When the 1200XL was introduced at the Winter
Consumer Electronics Show in December 1982, there was no sign of a new floppy drive. One reviewer noted that when he went looking all he could find was the "old model 810 clunkers", and speculated that "we will be seeing a new drive from Atari within the next half year". This prediction came true; when the 1200XL finally reached the market in June 1983, it was accompanied by the new
Atari 1050. It offered the new "enhanced" or "dual density" option that improved formatted capacity to 130 kB, although it was some time before DOS was upgraded to support it. The 1050 quickly replaced the 810 in the market. ==Description==