Nowadays, increasingly large and complex programs demand greater speed in information processing, which implies the search for faster and more efficient microprocessors.
The CISC architectures used since 15 years ago have allowed the development of a large number of software products. This represents a considerable investment and assures these processor families a growing market. However, simultaneously applications in which the processing capacity that can be obtained from the system. It is more important than the compatibility with the previous hardware and software increase. It is not only valid in the high capacity subsystems in the field of the so-called "embedded" systems, in which they always dominated the special solutions of high processing capacity but also for the "workstations". This kind of equipment has been introduced little by little in offices, in medicine and banks. Give a read to the article, Simple Implementation of MIPS Subset for having a glimpse of the topic.
In this type of equipment, the application software is run under the UNIX operating system, which is written in C language, so that the current RISC architectures are adapted and optimized for this high-level language.
For this reason, all renowned workstation producers have passed, in a few years, from the CISC processors to the RISC, which is reflected in the strong annual increase in the number of RISC processors, (the 32-bit RISC processors have seen its market grow by up to 150% per year). In a few years, the RISC will conquer 25-30% of the 32-bit market, despite the seemingly overwhelming volume of software based on processors with the CISC standard that has been marketed all over the world.
The MIPS-RISC architecture has found the greatest acceptance in the workstation sector. MIPS processors are manufactured and marketed by five semiconductor-producing companies, including NEC and Siemens. The processors of the five providers are compatible regarding terminals, functions, and bits. In the industrial field, there is a large number of applications that do not even exhaust the possibilities of 8-bit CISC controllers.
EXAMPLES OF RISC PROCESSORS
- Apple Power Mac G4 at 500 MHz
Apple Computers has announced a higher performance of its line of professional desktop systems Power Mac G4, which incorporates faster RISC processors working at 400, 450 and 500 MHz
The Power Mac G4 is available with 1 Mb of cache, AGP 2x video card with 16 Mb of video SDRAM, 10 Gb hard drive, DVD-ROM drive, FireWire and USB ports, 10/100 Ethernet and internal modem. 56K. The 450 and 500 MHz models increase the capacity of the hard disk to 20 and 27 GB respectively and include a ZIP drive.
The three Power Mac G4 models support Apple's Airport wireless network, which provides convenient and fast access to the Internet. Apple's Airport solution consists of the Airport card, which is installed on the computer, and the so-called Airport Base Station, which contains a 56K modem and a 10BASE-T Ethernet port to connect it with a telephone line, a cable modem or a local area network.
The new Power Mac G4 is available with a price ranging from 289,000 pesetas (1737 euros) of the cheapest model to 629,900 pesetas (3785 euros) of the most advanced model.
On the other hand, Apple has announced two new systems Macintosh Server G4 400 and 500 MHz; there is a 500 MHz model that incorporates Mac OS X Server software. All servers are equipped with 1 Mb of backside cache, ATI RAGE 128 Pro AGP 2x video controller with 16 Mb of SDRAM, 18 GB hard drive, DVD-ROM reader and 10/100 Ethernet.
- KRYPTON - 5 OR K5 FROM AMD
- Current Status: Commercial samples and the Predicted Speed: 120 MHz
- Estimated Performance: Between 109 and 115 SPECint92.
- Manufacturing Process: CMOS with three layers of metal.
- Size of Process Technology: 0.35 microns
- Four-way superscalar microarchitecture
- Uncoupled RISC type core
- Speculative execution with reordering of instructions
- Clock speeds lower than initially expected
- Extensive compatibility tests have delayed the launch
- PENTIUM PRO DE INTEL
- Current Status: Beginnings of production.
- Predicted Speed: 150 MHz
- Estimated Performance: Between 220 SPECint92; 215 SPECfp92
- Manufacturing Process: BiCMOS.
- Size of Process Technology: 0.6 microns
- High manufacturing price of the multichip package
- Optimized microarchitecture for 32-bit software, which has poor performance with 16-bit code
- Energy consumption and heat dissipation inappropriate for laptops
- Current Status: First production tests
- Estimated clock speed: 200 MHz
- Estimated performance: 300 SPECint92 and 600 SPECfp92
- Manufacturing Process: CMOS
- Size of Process Technology: 0.35 microns
This 64-bit chip has five functional pipelines so that you can run five instructions per clock cycle. With two double precision floating point units, the R10000 is optimized to support high floating point performance.
To optimize performance, external secondary cache memory has to be manufactured with expensive SRAM technology.
- SUN MICROSYSTEMS
- Current Status: Design
- Estimated Clock Speed: from 250 to 300 MHz
- Estimated performance: From 350 to 420 SPECint92 and from 550 to 660 SPECfp92
- Manufacturing Process: Five-layer metal CMOS.
- Size of Process Technology: 0.3 microns
The UltraSparc-II is a 64-bit superscalar four-way CPU that has not been optimized for high pure performance figures, but for multimedia and network applications.
The lack of hardware assistance to reorder instructions creates a great dependence on the quality of the compilers and requires the recompilation of the previous software to enjoy all the advantages of the UltraSparc-II chip.
What have we concluded?
Advances and progress in semiconductor technology have reduced the differences in processing speeds of microprocessors with memory speeds, which has had an impact on new technologies in the development of microprocessors.
The "era RISC" has reached all semiconductor manufacturers: AMD, Intel, MIPS, Motorola, ROSS, and all of them are products used by computer and workstation manufacturers: Apple, DEC, HP, IBM, SUN, etc. and its corresponding clones.
The design time of these products is significantly reduced, which decreases their final cost, and therefore, their expectations increase, to reach the market in a more appropriate time and with fewer possibilities of errors. Also, they are globally more efficient, smaller in size and lower in consumption, always offering clear technical advantages over the most advanced CISC.
RISC offers attractive solutions where a high processing capacity is required and an orientation towards high-level languages ??is presented, which is why the RISC processors have conquered the workstation sector.
Adopting typical techniques of the RISC processors in the new versions of CISC processors, it is tried to find new routes for the increase of the capacity of the families already established CISC. We can also expect the emergence of other technologies that compete with CISC and RISC.
Finally, we want to emphasize that the users make the decisions in the market, and here, the software or the concrete application plays a much more important role than the differences between the structures that are invaluable for the end user.
How do we see the future of the computing system?
The RISC will be launched to hunt the PC market. In addition to Power PC, cheap Acorn, Digital, AMD machines will appear. Intel will have to quickly remove the P6 (with HP RISC technology) if it does not want to go down in history. In any case, the standard PC will end sooner or later, and its successor will undoubtedly be a RISC. Now, what RISC? That will be seen over time.
It is clear that it seems that the future belongs to the RISC and multiprocessor systems unless the physics and electronics manage to overcome technological barriers to increase well above the current levels, speeds, and performance of a single CPU.