computer science

Siris 8

Siris 8 is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Siris 8 rather than just read about it. In short: Siris 8 is a discontinued operating system developed by the French company CII for its Iris 80 and Mitra 15 computers. It was later replaced by Honeywell DPS 7.

Key takeaways

Siris 8 belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Siris 8 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Siris 8 from memory before moving on to harder problems.

Reference excerpt

Siris 8 is a discontinued operating system developed by the French company CII for its Iris 80 and Mitra 15 computers. It was later replaced by Honeywell DPS 7. Jean Ichbiah worked at CII on the rewrite of the Siris 7 operating system of the Iris 80 to create a more successful version, used to operate a three processor Iris 80 in Évry. The first version of Siris 8 offered full compatibility with applications running on its predecessor Siris 7. Among its strong points were its excellent memory management, which took advantage of the extended virtual addresses and spaces of the Iris 80. Siris 8 was suitable for both scientific and business computing, as well as real-time applications. The first delivery of the uniprocessor version occurred in February 1972, and the dual-processor version in September 1972 for the French Atomic Energy Commission (CEA) Commissariat à l'énergie atomique. Siris 8 also included Transiris, networking software for transporting data to other computers. After the CII merger with Honeywell-Bull, the functionality of Siris was adapted for the GCOS system through an emulation processes, which made it possible to retain all of the Siris 8 customers. The final version of Siris 8, C10, was shipped in 1976.

Characteristics Before demand paged virtual memory was added in 1975, Siris 8 was described as having "two core partitions... one for resident 'batch' tasks, one for swapped time-shared tasks." It operated in four separate modes:

Batch processing comprising, local and remote Transaction processing Time sharing Real-time processing. The Siris 8 monitor consisted of a permanently resident portion and pageable segments. Batch jobs could be entered through the local or a remote card reader, or by the console operator. Timesharing could be started and stopped by the operator. A timesharing job was started by the DEMON task, which performed all terminal I/O. The system maintained three types of queues of work. The multiprogramming queue could run multiple jobs at a time, with jobs scheduled by priority. One to five Operational queues (Files d'attente d'exploitation) could run one job in each at a time, queued strictly by arrival time. A cataloged job queue was used for jobs submitted by the console operator; multiple jobs from this queue could be active at one time. Real-time jobs had access to special system services such as "[s]witching from slave mode to master mode and vice versa, time delays, abort recoveries." Transaction processing was performed by a subsystem called STRATEGE. The virtual address space available to the user could be up to 32 segments of 128 K (32-bit) words, or 16 MB.

References

External links Siris 8 description from the original commercial brochure, Fédération des Equipes Bull (translated to English)

Illustrations

Worked examples

Example 1 — a first encounter with Siris 8

Start with the simplest possible case. Write down what Siris 8 claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Siris 8 before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Siris 8 ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Siris 8

In research: Siris 8 appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Siris 8 in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Siris 8 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Discontinued operating systems, History of computing in France, Mainframe computers, so understanding it makes those chapters shorter.
In everyday life: Look for Siris 8 outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Siris 8” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Siris 8 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Siris 8 means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Siris 8 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Siris 8 in simple terms?

Siris 8 is a discontinued operating system developed by the French company CII for its Iris 80 and Mitra 15 computers. It was later replaced by Honeywell DPS 7.

Why does Siris 8 matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Siris 8?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Siris 8.