CHAPTER3: Processor Types and Specifications PART1 Computer Architecture

Processor Types and Specifications Microprocessor History: Processor is the engine of the PC, performs system’s calculating and processing. It is the most expensive single component. Intel had specific goal: to make semiconductor memory more practical and affordable.

Processor History By 1970:intel was known as a successful memory chip company. Because of Intel’s success in memory chip manufacturing and design, Japanese manufacturer Busicom asked Intel to design a set of chips for a family of high-performance programmable calculators

Processor History November 15, 1971 was the introduction of the 4- bit Intel 4004 CPU as part of the MCS-4 microcomputer set. The 4004 ran at a maximum clock speed of 740KHz (740,000 cycles per second, or nearly 3/4ths of a megahertz), contained 2,300 transistors in an area of only 12 sq. mm (3.5mm x 3.5mm)

Processor History The 4004 was designed for use in a calculator but proved to be useful for many other functions because of its inherent programmability. For example, the 4004 was used in traffic light controllers, blood analyzers. In April 1972, Intel released the 8008 processor, which originally ran at a clock speed of 500KHz (0.5MHz). The 8008 processor contained 3,500 transistors and was built on the same 10-micron process as the previous processor.

Processor History The big change in the 8008 was that it had an 8-bit data bus, which meant it could move data 8 bits at a time—twice as much as the previous chip. The next chip in the lineup was the 8080, introduced in April 1974. Running at a clock rate of 2MHz, the 8080 processor had 10 times the performance of the 8008.

Processor History Similar to the previous chip, the 8080 had an 8-bit data bus, so it could transfer 8 bits of data at a time. The 8080 could address up to 64KB of memory, significantly more than the previous chip. Motorola went on to create the 68000 series, which became the basis for the original line of Apple Macintosh computers. All these previous chips set the stage for the first PC processors.

PC Processor Evolution. PC Processor Evolution concentrated on four main areas: Increasing Transistor count and density. Increasing Clock cycling speed. Increasing the size of internal registers(bits). Increasing the number of cores in a single chip.

Processor Evolution Intel introduced the 286 chip in 1982. With 134,000 transistors, it provided about three times the performance of other 16-bit processors of the time. Featuring on-chip memory management, the 286 also offered software compatibility with its predecessors.

Processor Evolution In 1985 came the Intel 386 processor. With a new 32-bit architecture and 275,000 transistors, the chip could perform more than five million instructions every second (MIPS). in 1993, Intel introduced the first P5 family (586) processor, called the Pentium, setting new performance standards with several times the performance of the previous 486 processor.

Processor Evolution The year 2000 saw a significant milestone when both Intel and AMD crossed the 1GHz barrier, a speed that many thought could never be accomplished. In 2002, Intel released a Pentium 4 version running at 3.06GHz, the first PC processor to break the 3GHz barrier. and the first to feature Intel’s Hyper-Threading (HT) technology. This encouraged programmers to write multithreaded applications, which would prepare them for when true multicore processors would be released a few years later.

Processor Evolution In 2003, AMD released the first 64-bit PC processor: the Athlon 64. In 2005, both Intel and AMD released their first dual- core processors, basically integrating two processors into a single chip. Rather than attempting to increase clock rates, as has been done in the past, adding processing power by integrating two or more processors into a single chip enables future processors to perform more work with fewer bottlenecks and with a reduction in both power consumption and heat production.

Processor Evolution In 2008:intel released Core i series. Quad core processors with Hyper-threading (appearing as 8 cores for the OS)

16-bit to 64-bit Evolution Major change was to move from 16-bit internal architecture to 32-bit architecture.(IA-32) Now moving from 32-bit to 64-bit:backword compatibility. To make 64-bit reality:64-bit operating systems and drivers are needed.

Multi-core processors Multi-core processors have 4 or more full CPU cores in single CPU package. Enables single processor to perform the work of multiple processors. Get more work done in less time using multi-tasking. Processing speed and transistor counting are doubling every 2 years.

Processor Specifications Processors can be identified by: How wide they are.(Data and Address Bus, internal registers) How fast they are.(GHz: billion cycles/second). Data Bus=Front Side Bus. Even some processors have 64-bit data bus, they are classified as 32-bit processors because their registers 32-bit wide.

Intel Processor Specification Cores Voltage Register Data Bus Max Memory Transistor 8088 1 5v 16-bit 8-bit 1MB 29,000 386 32-bit 16MB 275,000 Pentium2 2.8v 64-bit 64GB 7.5M Core2due 2 1.3b 151M Core i7 4 1.4v 1TB 731M

Data I/O Bus: Speed and width of external data bus are important features of the processor. They define the rate at which data is moved into or out of the processor. Data in computer is sent as digital information Amount of data(Bandwidth) sent can be increased by either increasing the cycling time or the number of bits sent at a time.

Data I/O Bus: Once 64-bit architecture was reached, chip designers found they could not increase speed further—too hard to manage synchronizing 64-bit data. By going back to small bus width, it is possible to increase the data speed(cycle time) and get greater bandwidth.

Address Bus Set of wires carrying address information used to describe memory location. Each wire in the address bus carries a single bit. The more wires, the greater the total number of address locations. The width of address bus indicates the maximum amount of RAM to be addressed.

Address Bus Data and Address bus are independent. Chip designers can use what ever size they want for each. Usually chips with large data buses, have large address buses. Size of data bus: indication of chip’s information moving capability. Size of address bus: how much memory a chip can handle

Internal Registers(internal data bus) Indicates how much information the processor can operate on at one time. How it moves data around internally within the chip. Also referred as internal data bus. A register: holding cell with in the CPU. Ex: CPU adds numbers in two different registers, stores the result in third register

Internal Registers The register size also indicates: type of software or instructions CPU can run. 32-bit internal register=>runs 32-bit instructions processing 32-bit chunks of data.

Processor Modes Intel processors run in different modes. These modes refer to the different operating environment. Processor mode controls how the CPU sees and manages the system memory. Four Different Modes: Real Mode. Protected Mode. Virtual Real Mode 64-bit Extension Mode

Real Mode Real Mode: some times called 8086. PC could execute 16-bit instructions using 16-bit internal registers. Could address only 1MB memory (20-bit Address bus) Software was designed around the 16-bit instruction set and 1MB memory. Dos, Dos software, windows 1.x---3.x

Real Mode The 16-bit instruction mode of 8088 and 286 was known as Real Mode. Software running on the 16-bit real mode is usually single-tasking. Only one program can run at a time. No built-in protection exists to keep one program from over writing an other program or OS. If more programs are running  system crashes.

Protected Mode 386 processor came with 32-bit instruction capability. This chip could run 32-bit instructions. 32-bit operating systems and applications were required. The 32-bit mode is also called Protected Mode. Software running in this mode is protected from over writing. Protects from the system to crash.

Protected Mode Developing new Operating systems and applications taking advantage from 32-bit mode takes some time. Intel built a backward compatible real mode to 386. Enabling to run un modified 16-bit OS and applications. 32-bit chip running 16-bit OS uses only the first 1MB of the whole memory. Windows XP was the first OS running 32-bit instructions.

Virtual Real Mode(IA-32) Windows 32-bit backward compatibility. Virtual real mode: real 16-bit mode running inside 32-bit protected mode. Running Dos inside windows is creating virtual real mode inside protected mode. Since 32-bit mode enables multi-tasking, you can have several virtual real mode sessions running.

Virtual Real Mode Program running in virtual real mode can access up to 1MB of memory. The program believes is the first and the only megabyte of memory in the system. So each program gets its own 1MB address space.

IA-32e:64-bit Extension Mode An enhancement to the IA-32 architecture. 64-bit extension technology can run in real mode, IA-32 mode or IA-32e mode. AI-32-bit mode enables the processor to run protected mode and virtual real mode. IA-32e mode allows the processor to run in 64-bit mode and compatibility mode(both 64-bit and 32- bit at the same time)

64-bit Extension Mode Major difference between 32-bit and 64-bit is the memory support. In windows 32-bit system:4GB of physical memory. In 64-bit windows:192 GB of physical memory. Support for more memory means applications can preload more data in to memory which the processor can access much more quickly.