Computer Organization and Architecture Chapter 1
Why study computer organization and architecture?
- Design better programs, including compilers, operation systems and device drivers. -Optimize program behavior -Evaluate (benchmark) computer system performance.
The Third Generation: Integrated Circuit Computers(1965-1980)
Came with the microchip. Computers became faster, smaller and cheaper. IBM 360 DEC PDP-8 and PDP-11 Cray-1 supercomputer
Contro Units
Can be microprogrammed (a program written in a low-level language that is implemented by harder. or Hardwired (control units consist of hardware directly execute machine instructions).
Hard disc capacity
Determines the amount of data and size of programs you can store. The rotational speed is measured in 7200, the faster it rotates the faster it delivers data to RAM.
Computer Organization
Encompasses all physical aspects of computer systems. - Circuit design, control signals, memory types. "how does a computer work?"
Cache
Is a type of temporary memory that can be accessed faster than RAM.
Level 6 : User
Is composed of applications. We run programs such as words processors, graphics, games. The lower levels are nearly invisible from the User level.
Level 1 : Control
Is where the control unit makes sure that the instructions are decoded and executed properly
Parallel Processors/ Parallel Computing
Its when you use more than one processor to develop a faster, more powerful computer. The Blue Gene was the first. Blue Gene/P and Blue Gene/Q. They use multicore processor that allow to do multitasking.
The First Generation: Vacuum Tube Computer(1945-1953)
John Mauchly and J. Presper Eckert were the two principal inventors of the ENIAC, introduced to the public in 1946. The ENIAC was recognized as the first all-electronic, general purpose digital computer.
Clock frecuencia are mesurad in cycles per second or HERTZ
Most computer today operate in Gigahertz(GHz) generating billions of pulses per second.
Level 2 : Machine
Programs written in a computer's true language on a hardwire computer can be executed directly by the electronic circuits without any translators, compilers.
RAM
RAM is an acronym for Random Memory Access, it means that memory contents can be accessed directly if you know its location.
Level 3 : System Software
Responsable for multiprogramming, protecting memory, synchronizing processes. Instructions translated from assembly language to machine language are passed unmodified.
The Fourth Generation:VLSI Computers(1980-????)
SSI Small Scale Integration MSI Medium Scale Integration LSI Large Scale Integration VLSI Very Large Scale Integration.More than 10,000 components per chip. Intel introduced RAM 4Kilobits
Serial ports
Send data as a series of pulses along one or two data lines
Parallel ports
Send data as a single pulse along at least eight data lines.
Level 5 : the High-Level Language
Such as C, C++, Pascal, Prolog. These languages must be translated to a language the machine understands. (Compilers)
SDRAM
Synchronous Dynamic Random Access Memory. SRAM is much faster than conventional memory because it synchronize it self with a microprocessor's bus.
Level 4 : Assembly Language
The High-Level languages are first translated to assembly, which is then directly translated to machine language.
Computer Architecture
- refers to the logical and abstract aspects of system implementation. -instruction sets, formats, operation codes, data types, main memory access. "how do I design a computer?"
Generation Zero: Mechanical calculating machines (1642-1945).
-Calculating Clock was able to add and subtract as many as six digits- Wilhelm Schickard(1592-1635). -Pascaline Add and subtract, the first device used for practical purposes- Blaise Pascal(1623-1662). -Difference Engine Used the method of differences- Charles Babbage(1791-1871). -Punched card tabulating machines Used for encoding and compiling census data, boosted efficiency- Herman Hollerith (1860-1929).
There are many organizations that set computer hardware standards. Some of the most important are:
-The Institute of electrical and electronic engineers (IEEE). - The international Telecommunications Union(ITU). -The American National Standards Institute (ANSI). -The British Standard Institution (BSI). -The International Organization for Standardization.(ISO)
At the most basic level a computer is a device consisting in:
1. A processor to interpret and execute programs. 2. A memory to store both data and programs. 3. A mechanism for transfering data to and from the outside world.
Principle of equivalence of hardware and software
Any task done by software can also be done using hardware, and any operation performed directly by hardware can be done using software.
Rock's Law
Arthur Rock - Intel capitalist. "The cost of capital equipment to build semiconductors will double every four years". *For Moore's Law to hold, Rock's Law must fall and biceversa"
Moore's Law
Gordon Moore (Intel founder) "The density of transistors in an integrated circuit will double every year". Contemporary version: "The density of silicon chips doubles every 18 months". It can't hold forever, there are financial and physical limitations that must come into play.
Hot plugging
The ability to add and remove devices while the computer is running.
Plug and Play
The ability to configure devices automatically.
Level 0 : Digital Logic
The physical components of the computer system: the gates and wires.
USB
Universal Serial Bus, is an intelligent serial interface that is self-configuring (it supports "plug and play" and "hot plugging").
Second Generation: Transistored Computers (1954-1965)
Vacuum tubes were replaced by transistors, because they consume less energy and are more reliable.
Computer Level Hierarchy
We can imagine the machine to be build from distinct hierarchy levels, in which each level has a specific function. We call each hypothetical computer at each level a virtual machine. Each virtual machine executes its own particular set of instructions, calling upon machines at lower level to carry a task when necessary.
