MediaGX

Key takeaways

MediaGX 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 MediaGX to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of MediaGX from memory before moving on to harder problems.

Reference excerpt

The MediaGX CPU is an x86-compatible processor that was designed by Cyrix and manufactured by National Semiconductor following the two companies' merger. It was introduced in 1997. The core is based on the integration of the Cyrix Cx5x86 CPU core with hardware to process video and audio output (XpressRAM, XpressGRAPHICS, XpressAUDIO). Following the buyout of Cyrix by National Semiconductor and the sale of the Cyrix name and trademarks to VIA Technologies, the core was developed by National Semiconductor into the Geode line of processors, which was subsequently sold to Advanced Micro Devices. Whether this processor belongs in the fourth or fifth generation of x86 processors can be considered a matter of debate as the processor was based on the 5x86 (a scaled down version of the Cyrix 6x86). While the 5x86 was intended to compete with the Intel Pentium line, the 5th generation x86, it was designed to interface with a 4th generation (80486) motherboard and had only the 486's instruction set, lacking the ability to run software requiring the Pentium's new instructions. The MediaGX CPU was mostly used for subcompact laptops. It was also used in the CTX EzBook V92C266, Compaq Presario 1220 and 1230 laptops, Compaq Presario 2100 and 2200 desktops, Casio Cassiopeia Fiva MPC-100 series subnotebook and MPC-501 tablet PCs, and many others, as well as in high-performance embedded applications such as the Pinball 2000 arcade pinball system and Atari Games arcade platforms. Sun Microsystems used MediaGXm in the Dover JavaStation.

History The MediaGX was launched on February 20, 1997. Compaq would be using the chip in some of their computers such as the Presario 2000, which went on sale for $999. This was due to a partnership between Cyrix and Compaq. The MediaGX was first available in speeds of 120 and 133 MHz with pricing of $79 and $99. The 150 MHz version of the MedixGX was available by June of 1997. This version of the chip would be used in the Presario 2120. The 150 MHz chip would cost $99 each in bulk quantities with the 133 and 120 MHz costing $88 and $60.

Specifications

Virtual Subsystem Architecture Virtual Subsystem Architecture (VSA) emulates a presence of the real hardware VGA (XpressGRAPHICS) and Sound Blaster (XpressAUDIO). The access to the hardware resources traps via BIOS and emulates in the System Management Mode (SMM), enabling it to execute transparently to the operating system, drivers and applications.

Media GX Manufacturing process: 0.4 μm Cache: L1 16 KB unified Core speed: 120, 133, 150 MHz Bus speed: 33 MHz

Media GXi

Cyrix MediaGXi is an improved version of the MediaGX.

Manufacturing process: 0.35 μm Cache: L1 16 KB unified Core speed: 120, 133, 150, 166, 180 MHz

MediaGXm The MediaGXm is an improved MediaGX with an implementation of the MMX enhanced instruction set. Manufacturing process: 0.35 μm 4-layer metalCMOS process Core speed: 180–266 MHz Bus speed: 33 MHz Cache: L1 cache size 16 KB write-back 4-way set associative unified I/D cache. Or 12-Kbyte unified L1 Cache and 4K scratchpad for SMM & Graphics. Integrated peripherals: PCI controller Display controller and 2D graphics accelerator Hardware MPEG-1 supports full-screen video playback 16-bit audio subsystem Sound Blaster 16/Pro compatible 64-bit SDRAM controller V core: 2.9 V V I/O: 3.3 V Package: 320-pin Ceramic PGA; 352-ball BGA System chipset: Cx5520 352-pin BGA National Semiconductor offered this processor under the name Geode GXM.

Comparison to other contemporary processors The MediaGX platform does not provide support for external Level-2 cache memory, typical for motherboard designs of the period. All of the cache must be on the processor die. MediaGX processors can only run on motherboards specifically designed for the same model of the processor due to tight integration between the processor and its companion chipset. The graphics, sound, and PCI bus ran at the same speed as the processor clock also due to tight integration. This made the processor appear much slower than its actual rated speed. However, the graphics system is able to use the main system memory providing for significant cost savings on the basic systems and embedded controllers in the market for this platform.

See also Cyrix Cyrix Cx5x86 National Semiconductor Geode (processor) AMD

References

Gwennap, Linley (10 March 1997). "MediaGX Targets Low-Cost PCs". Microprocessor Report.

External links GXM Product Folder at National Semiconductor (archived version 2007) AMD Geode Solutions Cyrix MediaGX and National Semiconductor Geode Information Cyrix MediaGX Archived 2011-01-02 at the Wayback Machine Cyrix

Illustrations

Worked examples

Example 1 — a first encounter with MediaGX

Start with the simplest possible case. Write down what MediaGX 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 MediaGX 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 MediaGX 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 MediaGX

In research: MediaGX 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 MediaGX 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: MediaGX is common in secondary-school and first-year university syllabi. It links to neighbouring topics Computer-related introductions in 1997, Cyrix x86 microprocessors, Embedded microprocessors, so understanding it makes those chapters shorter.
In everyday life: Look for MediaGX 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.

How to study MediaGX in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what MediaGX 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 MediaGX out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is MediaGX in simple terms?

The MediaGX CPU is an x86-compatible processor that was designed by Cyrix and manufactured by National Semiconductor following the two companies' merger. It was introduced in 1997.

Why does MediaGX 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 MediaGX?

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 MediaGX.