Week 2-session 1-Computer History,.Architecture & Catergories of Computers

Computer History

 

 

 

The computer was not fully equipped with all the fantastic capabilities since it started. Just like us, it grew step by step to the luxurious models we see now. And just like us human beings, computers have their own history and their own generations. Here’s a glimpse at the history of computers.

 

 

• Pre-computers and early computers (before 1940): Our ancient civilizations had the ability to count and compute. And the basic things they used to do these were the Abacus (earliest recorded calculating device), slide ruler, mechanical calculator, punch card, tabulating machine and sorter. 

• First Generation (1940-1950) : Vacuum Tube; This was designed by Mauchly & Echert, built by US army to calculate trajectories for ballistic shells during world war ll

• Second Generation (1950-1964): Transistors; Vacuum tubes were replaced by transistors by William Shockley, John Bardeen and Walter Brattain. Transistors used the first operating systems which handled one program at a time. It also included on-off switches which were controlled electronically.

• Third Generation (1964-1974) : Integrated Circuits (IC); These computers had microprocessor chips that combined thousands of transistors and an entire circuit on one computer chip. Also, there were more than one computer models with different performance characteristics.

• Fourth Generation (1974-Present) : VLSI / ULSI ; VLSI stands for Very Large-scale integration and ULSI stands for Ultra large-scale integration. Computers in this generation have millions of transistors combined. They are also equipped with single-chip processors. It was in this generation that Personal Computers (PCs) were invented.

• Fifth Generation (now and the future): Computers in this generation are based on artificial intelligence. Computers are made to think, reason and learn! The primary means of input in these computers are voice and touch. The computers in this generation could be the ones that utilize nanotechnology or they can come as entire general-purpose computers.

If you compare the first generation computers to the computers these days, there will be a huge difference. This is an example as to how human beings learn by doing. Someone started it and the rest of them remodeled it and came up with much better and compact designs with more capabilities. If they had just stopped there, without thinking of remodeling and improving it, we won’t have the easy PCs today to complete huge chunks of office work!

 

Computer Architecture

All our human bodies are created according to an architecture. So are computers. These architectures have never changed since 1946 which means that the components of this architecture are essentials for each and every computer.

 

 

• Processor: the centre for manipulation and control
• Memory: storage for instruction and data for currently executing programs
• I/O System: Controller which communicates with “external” devices: secondary memory, display devices, networks.
• Data-path & control: Collection of parallel wires, transmits data, instructions , or control signal.

Since 1946, all computers have had these components. Just like we have all had brains, hearts and nervous systems.

Catergories of Computers

These computers are categorized based on size, capability and price.

• Embedded computer

Embedded computers are miniature computers that are embedded into a specific product to perform a specific function.

•  Mobile Computers

The best examples are our mobile phones which easily fit on our lap/hand and which contains built-in computing or internet capabilities.

•  Personal computers

These can be portable computers like laptops and notebooks or desktop computers. Personal computers are fully functioning and are designed for a single user at a time.

• Midrange Servers

These look like small cabinets, hosting data and programs available to a small group of users.

• Mainframe computers

These are powerful computers consuming large space which are used to host a large amount of data and programs available to a wide range of users.

• Super computers

These are extremely powerful computers used for complex computation and processing.