Chapter 1 Introduction Chapter Contents A Brief History

Chapter 1 – Introduction

Chapter Contents • • A Brief History of Computing The Von Neumann Model The System Bus Model Levels of Machines A Typical Computer System Classes of computer Trends in Computer architecture

COA - Definitions • Computer organization is concerned with the way the hardware components operate and the way they are connected together to form computer system. • It includes Hardware details transparent to the programmer such as control signal and peripheral. • It describes how the computer performs. Example: circuit design, control signals, memory types this all are under computer organization.

• Comp architecture is concerned with the structure and behavior of comp system as seen by the t user. • It includes information , formats , instruction set and techniques for addressing memory. • It describes what the computer does.

Some Definitions • Computer architecture deals with the functional behavior of a computer system as viewed by a programmer (like the size of a data type – 32 bits to an integer). • Computer organization deals with structural relationships that are not visible to the programmer (like clock frequency or the size of the physical memory).

Wolf Radius Bone • Wolf radius bone ca. 25, 000– 30, 000 B. C. ( years ago) showing 55 cuts in groups of five, suggesting a rudimentary form of multiplication or division. • “Counting” or ” tallying” was done by making notches in objects such as bones. (Source: Illustrated London News, October 2, 1937. )

Tally Sticks Original wooden tally sticks from Westminster, England, ca. 1250– 1275 A. D. (12 th century)

Chinese Abacus • Representation of 39, 017 on a Chinese abacus.

Cylinder Music Box • Victorian Swiss cylinder music box, dated 1862. • Mechanical devices for controlling complex operations

Pascal’s Calculating Machine • Performs basic arithmetic operations (early to mid 1600’s). Does not have what may be considered the basic parts of a computer.

• Pascal developed a mechanical calculator to help in his fathers tax work. • The Pascal calculator “Pascaline” contains 8 dials that connect to a drum.

Babbage’s Difference Engine #1 • Working portion of Babbage’s Difference Engine No. 1, which is the first known automatic calculator.

• Charles Babbage (1791 -1871) is sometimes referred to as father of computer. • He never built a practical version of machines he designed. • Babbage’s machine had a means for reading input data , storing data, performing calculations, producing output data, and automatically controlling the operations of the machine.

Enigma • Siemens Halkse T -52 Sturgeon (Enigma) cipher machine. • Exchanging Encrpted mesages by Enigma

Colossus • The colossus was a successful code breaking machine that came out of Bletchley park, it was based on concept developed by Max Newman and designed and constructed by Tommy Flowers. • Its purpose is to break the Lorenz encoding • solve a problem posed by mathematician Max Newman

The ENIAC: ENIAC stands for Electronic Numerical Integrator and Computer.

• ENIAC was a modular computer, composed of individual panels to perform different functions. • Twenty of these modules were accumulators, which could not only add and subtract but hold a tendigit decimal number in memory. • ENIAC contained 17, 468 vacuum tubes, 7200 crystal diodes, 1500 relays, 70, 000 resistors, 10, 000 capacitors and approximately 5, 000 hand-soldered joints. It weighed more than 30 short tons (27 t), was roughly 8 × 3 × 100 feet (2. 4 m × 0. 9 m × 30 m) in size, occupied 1800 ft 2 (167 m 2) and consumed 150 k. W of electricity

• The ENIAC consists of 18000 vacuum tubes, which make up the computing section of the machine. • Programming and data entry are performed by setting switches and changing cables. • There is no concept of stored program, and no central memory unit. • It was used for nine years after 1946

EDVAC (Electronic Discrete Variable Automatic Computer) • was one of the earliest electronic computers. Unlike its predecessor the ENIAC, it was binary rather than decimal, and was a stored program computer. • Functionally, EDVAC was a binary serial computer with automatic addition, subtraction, multiplication, programmed division and automatic checking with an ultrasonic serial memory capacity of 1, 000 44 bit words. • EDVAC's average addition time was 864 microseconds and its average multiplication time was 2, 900 microseconds. • By 1960 EDVAC was running over 20 hours a day with error-free run time averaging eight hours.

• The EDVAC as installed in Building 328 at the. Ballis tics Researc h Laborat ory.

EDVAC • The first working demonstration of a stored program computer, however was designed and developed by FC Williams and Tom kilbum at the university of Manchester. • This was small scale experimental machine (known as baby) on june 21, 1948. • Enhancements to the Baby led to the Manchester Mark 1, which became fully operational in october 1949.

Moore’s Law: is the observation that, over the history of computing hardware, the number of transistors in a dense integrated circuit has doubled approximately every two years.

• Moore's law" is the observation that, over the history of computing hardware, the number of transistors in a dense integrated circuit has doubled approximately every two years. • The observation is named after Gordon E. Moore, co-founder of the Intel Corporation and Fairchild Semiconductor, whose 1965 paper described a doubling every year in the number of components per integrated circuit

The von Neumann Model • The von Neumann model consists of five major components: (1) input unit; (2) output unit; (3) arithmetic logic unit; (4) memory unit; (5) control unit.

The System Bus Model • A refinement of the von Neumann model, the system bus model has a CPU (ALU and control), memory, and an input/output unit. • Communication among components is handled by a shared pathway called the system bus, which is made up of the data bus, the address bus, and the control bus. • There is also a power bus, and some architectures may also have a separate I/O bus.

Upward Compatibility • The invention of the transistor led to a rapid development of computer hardware and with this development came a problem of compatibility • Each new computer model had a new architecture and old software would not run on the new hardware. • Upward compatibility allows a user to upgrade to a faster.

Levels of Machines • There a number of levels in a computer, from the “user level” down to the “transistor level”. • Progressing from the top level downward, the levels become less abstract as more of the internal structure of the computer becomes visible. • One of the reasons for enormous success of the digital computer is the extent to which these levels of abstraction are separate or independent from one another.

• The Levels

• User level: User interacts with the computer by running programs such as word processors, spreadsheets programs, or games. • High level language level: HLL such as C, java, Pascal has interacted with computer at this level. At this level the programmer sees the data types and instructions of the high level language, language but needs no knowledge of how these data types are actually implemented in the machine.

• Assembly language/Machine code level: The compiler translates the source code into the actual machine instructions, is referred as machine language or machine code. • Assembler

• The Control level: One way implementing control unit by “hard wiring” the control unituni : the control unit interprets the machine instructions one by one, causing the specified register transfer or other action to occur. • Hardwired control units have the advantages of speed and component count, but difficult to design and modify. • Micro program : is a small program written in an lower level language and implemented in the hardware, whose job is to interpret m/c language instructions.

• Functional unit level: Register transfer is implemented by the control unit , move the data in and out of “functional units”. It includes internal CPU registers, the ALU and main memory. Logic gates, Transistors, and wires: At the very lowest level a computer consists of electrical components such as transistors and wires which make up the logic gates.

A Typical Computer System

The Motherboard • An AMD Opteron 200 based motherboard.

Manchester University Mark 1 / Baby • The Manchester University Mark 1, showing the Manchester Baby portion which was made operational on 21 June 1948.