Altos Computer Systems

According to a brief history of the company, which ran as an advertisement on their 10th anniversary, Altos Computer Systems was started by Dave Jackson in 1977 when he designed a single-board microcomputer in a room he rented on Stevens Creek Boulevard. According to this account, the company bootstrapped itself with profitable sales from the beginning, with a revenue of $260,000 in the first year. Jackson named the company after Los Altos Hills, California, where he lived.

In an interview from May 1979, the company's vice-president Roger Vass described the Altos' strategy at the time as selling OEM computer systems. Vass also said that the company's revenue had reached an annual figure of $5M that year, after 15 months of operations. The company's single-board computer product was named "Sun-Series 8000" at this point; it was based on 4-MHz Z80 processor and shipped with 32 KB of RAM, expandable to 64 KB. Altos eschewed using the (fairly standard at the time) S-100 bus, but packed their board with a disk controller (which could connect up to two 8-inch Shugart drives), two serial and one parallel port, while also leaving room for another optional Z80 to be used as DMA controller and an optional AMD 9511 floating-point coprocessor. As operating system, this machine could use CP/M or Oasis.

ACS 8000

In the aforementioned interview, Vass also described their plans for the company's first multi-user computer, based on a CP/M-derived executive that they called AMEX (Altos Multiuser Executive). Their new design planned to support up to four users, by providing each user with its own 48 KB of dedicated program memory (addressable by the 8-bit Z80 processor through bank switching), while the 16 KB of memory for the operating system's image could be shared by all users. An advertisement for the "Sun-Series ACS8000-6" sold under Altos' own brand appeared in the November 1979 issue of Byte, and indeed promised to support up to four users by means of its AMEX kernel, and supporting a maximum system memory of 208 KB. The ACS 8000 could run at least three multi-user operating systems: Altos' own AMEX, Oasis, or MP/M. The sample code for the Banked XIOS implementation published in the MP/M II System Implementors Guide was written by Altos (and carries a disclaimer that it only works as-is with their Sun Series 8000).

The "8000" contained in the name of Altos' first series of computer did cause some confusion in the marketplace because its name may have suggested the inclusion of the 16-bit Zilog Z8000 processor, which had just been released in 1979, although Altos' ACS-8000 did not use this processor, but the older 8-bit Z80. A 1981 review in Computerworld, comparing the ACS 8000 with other multi-user systems, found that Altos' Z80 processor was underpowered, especially for CPU-intensive tasks (most other multi-user systems used 16-bit processors by then), but the ACS-8000 was found adequate for multi-user order entry systems. A configuration with a 10-MB hard-drive plus a 1-MB 8" floppy drive, bundled with a printer and one terminal was priced at $12,340 (the same machine but with four terminals was $15,625), which was considerably less than most other multi-user systems, which were typically priced in the $25,000–$50,000 range. Altos thus carved for itself a niche in the low-cost multi-user systems. The lack of any expansion slots was judged however as fairly limiting. Their omission, as well the omission of circuitry that would have been necessary to connect the Z80 to the industry-standard S-100 bus, which was Intel-centric (around the Intel 8080) was one of the reasons why the ACS-8000 could keep its cost low (relative to its epoch).

ACS 8600

Alto's next major product line would indeed use a 16-bit processor, but it would be Intel's 8086, seemingly chosen for reasons of availability both in terms of the hardware itself and of the CP/M-86 operating system. The ACS-8600 series, announced in October 1980 as "ACS 16000" and launched in November 1981, was based on the 8086 with a 8089 standard communications co-processor. Supported operating systems were CP/M-86, MP/M-86, Oasis-16, and—for the first time—Xenix. This was still a machine based on 8" disk technology, both for floppy and hard disks. The entry level unit, equipped with 128 KB RAM and a single 1-MB floppy drive was priced at $8,990 at launch, while the high end version, with 512 KB of RAM and a 40 MB hard drive launched at $18,980. By 1983, Altos was the leading 8086-based Unix vendor, running Xenix.

ACS 68000

In 1982, Altos diversified its product line yet again with the introduction of the ACS68000, which was based on the Motorola 68000 processor (at 8 MHz) and was intended to support up to 16 users. It shipped with Unix System III initially. The machine was initially offered with a 40 MB disk drive (and sticker price of $14,500), while an 80-MB disk version was offered in the first quarter of 1983 (for $16,500). As business packages were generally lacking for the ACS 68000, it was mostly sold through OEMs rather than Altos' own dealer network. The first version of the Oracle database which ran on Unix (version 3) was announced supporting the ACS68000 among other similar "supermicro" computers like the Tandy Model 16, and the Fortune 32:16. Altos also invested in Informix Corporation, owning 19% of the database vendor's initial public offering.

Subsequent products

Other multi-user computers:

Altos 580 (1983), 5-5, and 5-15 were somewhat cheaper Z80 machines, based on 5.25" drives.