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This is a personal recollection on the Move fire on May 13, 1985
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 Data General Eclipse S/130 front panel | |
| Manufacturer | Data General |
|---|---|
Product family | Nova |
| AOS | |
The Eclipse by Data General is a line of 16-bit minicomputers released in early 1974 and sold until 1988. The Eclipse was based on many of the same concepts as the Data General Nova, but included support for virtual memory and multitasking more suitable to the small office than the lab. It was also packaged differently for this reason, in a floor-standing case the size of a small refrigerator. The Eclipse series was supplanted by the 32-bit Data General Eclipse MV/8000 in 1980.
The Data General Nova was intended to outperform the PDP-8 while being less expensive, and in a similar fashion, the Eclipse was meant to compete against the larger PDP-11 computers. The Nova had a simple architecture with four 16-bit accumulator registers, the latter two also serving as index registers. The Eclipse kept this layout, and was compatible with Nova code using them, but added four 64-bit registers for floating-point arithmetic support (if installed). Like the Nova, the Eclipse did not directly support byte addressing; the smallest unit of addressable and writable memory is the 16-bit word. A major improvement was the addition of a processor-managed stack pointer, which the Nova lacked.[1] The stack pointer was added into the later Nova 3 machines in 1975, and also used on the later 32-bit Data General Eclipse MV/8000.
The largest change to the programming model was the Memory Allocation and Protection (MAP) system. This broke down main memory into a series of 2,048 byte blocks, and any one program could used up 32 of them, for a total of 64 kb. The maximum memory as a whole expanded from 64 to 256 kb, but MAP made this change invisible to the programs. To existing Nova software, nothing changed, but for software written explicitly for the Eclipse, programs could share blocks of memory with other programs.[2] This was a common architecture at the time for supporting timesharing, which was a primary goal of the Eclipse design.
There were initially two series, S and C, and three individual models of the Eclipse, 100, 200 and 300. The S/100 was the basic model, lacking MAP and the floating point option, both of which were present on the S/200. The C/300 added a collection of additional instructions to the S/200, intended to help implement common routines seen in business applications like converting strings between different character sets, or reading and writing numbers to and from different formats including strings. This Commercial Instruction Set also included fixed-point arithmetic instructions, which were commonly used in currency calculations as they did not lose accuracy.[a] To implement these, the C/300 used a modified processor known as the Extended Arithmetic Processor.[2] Another difference between the S and C series was that the former included a writable control store, which allowed the user to write their own instructions and store them in the processor for fast execution.[3]
Production problems with the Eclipse led to a rash of lawsuits in the late 1970s, after new versions of the machine were pre-ordered by many DG customers and then never arrived.[4] After over a year of waiting, some decided to sue the company, while others simply cancelled their orders and went elsewhere.[4] It appeared that the Eclipse was originally intended to replace the Nova outright, also evidenced by the fact that the Nova 3 series released at the same time was phased out the next year. However, strong continuing demand resulted in the Nova 4, perhaps as a result of the continuing problems with the Eclipse.
As was the case with the earlier Nova series, the Eclipse underwent continual updating, following changes in semiconductor manufacturing. Unlike the Nova, these generally kept the name of the corresponding original model, adding a model number such that, for instance, the S/100 was replaced by the S/130 and 140.[5]
The main differences in later models was the expansion of the memory model to allow for ever-increasing amounts of main memory. The S/140 supported up to 1 MB. Other changes included the addition of integer multiplication and division in the base unit, as well as a version of the CIS becoming standard on all models.[6]
The AOS operating system was quite sophisticated, advanced compared to the PDP-11 offerings, with access control lists (ACLs) for file protection.
The original Cray-1 system used an Eclipse to act as a Maintenance and Control Unit (MCU). It was configured with two Ampex CRTs, an 80 MB Ampex disk drive, a thermal printer, and a 9-track tape drive. Its primary purpose was to download an image of either the Cray Operating System or customer engineering diagnostics at boot time. Once booted, it acted as a status and control console via RDOS station software.
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Source: Wikipedia. Article content is retrieved live through the MediaWiki API.
The Eclipse by Data General is a line of 16-bit minicomputers released in early 1974 and sold until 1988. The Eclipse was based on many of the same concepts as the Data General Nova, but included support for virtual memory and multitasking more suitable to the small office than the lab. It was also packaged differently for this reason, in a floor-standing case the size of a small refrigerator. The Eclipse series was supplanted by the 32-bit Data General Eclipse MV/8000 in 1980.
The Eclipse MV/8000 was the first in a family of 32-bit minicomputers produced by Data General during the 1980s. Codenamed Eagle during development, its architecture was a new 32-bit design backward compatible with the previous 16-bit Eclipse series. The development of the computer and the people who worked on it were the subject of Tracy Kidder's book The Soul of a New Machine. The MV/8000 was succeeded by the MV/6000, MV/8000-II, MV/2000, MV/2500, MV/4000, MV/10000, MV15000, MV/20000, MV/30000 and MV/40000. Later models such as the MV/40000 were SMP systems with hot-swappable components. The Eclipse MV was a 32-bit CISC architecture with a 4 gigabytes logical address space, having a physical address space from 0 to 2 megabytes. The 4 GB address space was divided into eight rings of 512 MB each with a privilege mechanism mapped onto the rings. The outermost ring, ring-7, was the least privileged. The inner-most ring, ring-0, was the most privileged. The AOS/VS operating system supported the notion of lightweight "tasks" as well as processes. A single process could start various tasks that would all share a global address space (similar to modern "threads"). Tasks were very easy to use from Data General's FORTRAN compiler, and allowed faster context switching than using full processes. One could also start subtasks, using so-called "Son" batch process. This was done using the CLI (Command Line Interpreter). It resulted in a de facto online batch process. This process would, however be killed as soon as the user would log off. The MV/8000 had only two "true" batch processes, as not to frustrate the online processes. The "plus" of the online batches was that they ran with the same priority as the normal online processes.
The Nova is a series of 16-bit minicomputers released by the American company Data General. The Nova family was very popular in the 1970s and ultimately sold tens of thousands of units. The first model, known simply as "Nova", was released in 1969. The Nova was packaged into a single 3U rack-mount case and had enough computing power to handle most simple tasks. The Nova became popular in science laboratories around the world. It was followed the next year by the SuperNOVA, which ran roughly four times as fast, making it the fastest mini for several years. Introduced during a period of rapid progress in integrated circuit (or "microchip") design, the line went through several upgrades over the next five years, introducing the 800 and 1200, the Nova 2, Nova 3, and ultimately the Nova 4. A single-chip implementation was also introduced as the microNOVA in 1977, but did not see widespread use as the market moved to new microprocessor designs. Fairchild Semiconductor also introduced a microprocessor version of the Nova in 1977, the Fairchild 9440, but it also saw limited use in the market. The Nova line was succeeded by the Data General Eclipse, which was similar in most ways but added virtual memory support and other features required by modern operating systems. A 32-bit upgrade of the Eclipse resulted in the Eclipse MV series of the 1980s.
Data General Corporation was an early minicomputer firm formed in 1968. Three of the four founders were former employees of Digital Equipment Corporation (DEC). Their first product, 1969's Data General Nova, was a 16-bit minicomputer intended to both outperform and cost less than the equivalent from DEC, the 12-bit PDP-8. A basic Nova system cost two-thirds or less than a similar PDP-8 while running faster, offering easy expandability, being significantly smaller, and proving more reliable in the field. Combined with Data General RDOS (DG/RDOS) and programming languages like Data General Business Basic, Novas provided a multi-user platform far ahead of many contemporary systems. A series of updated Nova machines were released through the early 1970s that kept the Nova line at the front of the 16-bit mini world. The Nova was followed by the Eclipse series which offered much larger memory capacity while still being able to run Nova code without modification. The Eclipse launch was marred by production problems and it was some time before it was a reliable replacement for the tens of thousands of Novas in the market. As the mini world moved from 16-bit to 32, DG introduced the Data General Eclipse MV/8000, whose development was extensively documented in the popular 1981 book, The Soul of a New Machine. Although DG's computers were successful, the introduction of the IBM PC in 1981 marked the beginning of the end for minicomputers, and by the end of the decade, the entire market had largely disappeared. The introduction of the Data General/One in 1984 did nothing to stop the erosion. In a major business pivot, in 1989 DG released the AViiON series of scalable Unix systems which spanned from desktop workstations to departmental servers. This scalability was managed through the use of NUMA, allowing a number of commodity processors to work together in a single system. Following AViiON was the CLARiiON series of network-attached storage systems which became a major product line in the later 1990s. This led to a purchase by EMC, the major vendor in the storage space at that time. EMC shut down all of DG's lines except for CLARiiON, which continued sales until 2012.
Before the 1921 destruction of Tulsa’s Greenwood District, Black residents had created a remarkable center of business and community life. The district included stores, professional offices, entertainment venues and homes owned by Black citizens. Understanding Greenwood means learning what was built—not only what was burned.
MORE →Mae Jemison, aboard Space Shuttle Endeavour in 1992.