In ,computer architechture a bus is a subsystem that transfers data between computer components inside a computer or between computers. Unlike a point-to-point connection, a bus can logically connect several peripherals over the same set of wires. Each bus defines its set of connectors to physically plug devices, cards or cables together.
Early computer buses were literally parallel electrical buses with multiple connections, but the term is now used for any physical arrangement that provides the same logical functionality as a parallel electrical bus. Modern computer buses can use both parallel and bit-serial connections, and can be wired in either a multidrop (electrical parallel) or daisy chain topology, or connected by switched hubs, as in the case of USB.
A control bus is (part of) a computer bus, used by CPUs for communicating with other devices within the computer. While the address bus carries the information on which device the CPU is communicating with and the data buss carries the actual data being processed, the control bus carries commands from the CPU and returns status signals from the devices, for example if the data is being read or written to the device the appropriate line (read or write) will be active (logic zero).
An address bus is a computer bus, controlled by CPUs or DMA-capable peripherals for specifying the physical addresses of computer memory elements that the requesting unit wants to access (read or write).
The width of an address bus, along with the size of addressable memory elements, generally determines how much memory can be directly accessed. For example, a 16-bit wide address bus (commonly used in the 8-bit processors of the 1970s and early 1980s) reaches across 216 (65,536) memory locations , whereas a 32-bit address bus common in PC processors as of 2004 update can address 232 4,294,967,296 locations. Some microprocessors, such as the Digital Compaq Hewlett-Packard Alpha 21264 and Alpha 21364 have an address bus that is narrower than the amount of memory they can address. The address bus is clocked faster than the system or memory bus, enabling it to transfer an address in the same amount of time as an address bus of the same width as the address.
In most microcomputers such addressable "locations" are 8-bit bytes, conceptually at least. In such case the above examples translate to 64 kilobytes (KB) and 4 gigabytes (GB) respectively. However, it should be noted that accessing an individual byte frequently requires reading or writing the full bus width a word at once. In these instances the least significant bits of the address bus may not even be implemented - it is instead the responsibility of the controlling device to isolate the individual byte required from the complete word transmitted. This is the case, for instance, with the VESA Local Bus which lacks the two least significant bits, limiting this bus to aligned 32 bit transfers.
Historically, there were also some examples of computers which were only able to address larger words, such as 36 or 48 bits long.
Wednesday, December 10, 2008
CPU rear/back
1.Power Supply unit
2.Ps/2 ports
3.USB port
4.Parallel port
5.Serial port
6.AGP port
7.Lan port
8.Expansion slot
Basic parts of a motherboard
A.CPU slot G.PS/2 port
B.RAM socket I.IDE for FDD
C.IDE for the primary&secondary Devices J.Power terminal for mainboard
D.AGP slot K.CMOS battery
E.PCI slot L.Auxiliary ports
F.Serial & parallel port M.USB port
G.PS/2 port
I.IDE slot for FDD
J.Power terminal for mainboard
K.CMOS battery
L.Auxiliary ports
M.USB port
history of computer hardware
Computer Hardware - A History
Computer hardware has transformed in the last few decades as computers evolved from bulky, beige monsters to sleek and sexy machines. Computer Hardware – a History The dictionary defines ‘computer’ as any programmable electronic device that can store, retrieve, and process data. Computer Hardware evolved as data storage, calculation and data processing became important elements in work and life. In fact, the earliest computer Hardware is thought to be record keeping aids such as clay shapes that represented items in the real world – the early mechanics of merchants and accountants of the past. From the abacus and the slide rule came analogue and later, the electronic computer Hardware known today. A timeline of the history of computer Hardware: 1632 the first mechanical calculator was built by Wilhelm Schickard. It used cogs and gears and became the predecessor for computer Hardware. 1801 punched card technology began and by 1890 sorting machines were handling data, the first computer Hardware and installations used punched cards until the 1970s. 1820, Charles Xavier Thomas created the first mass-produced calculator. 1835, Charles Babbage described his analytical engine, which was the layout of a general-purpose programmable computer. 1909, Percy Ludgate designed a programmable mechanical computer. 1914, a central component in computer Hardware – the binary numeral system- was described by Leibniz. 1930s, desktop mechanical calculators, cash registers and accounting machines were introduced. By the 1960s, calculators advanced with integrated cuircuits and microprocessors. Digital computer Hardware replaced analogue computers. Digital computer Hardware The era of the computer as we know it today began with developments during the Second World War as researchers and scientists were spurred on by the military. 1960s and beyond ‘Third generation’ computer Hardware took off post 1960 thanks to the invention of the integrated circuit or microchip. This led to the microprocessor which in turn led to the microcomputer – computer Hardware that could be owned by individuals and small businesses. Steve Wozniak co-founded Apple Computer and is credited with developing the first mass market computer, although the KIM-1 and Altair 8800 came first. Evolution in computer Hardware After the 1970s the personal computer and evolution in computer Hardware exploded across the western world. Microsoft, Apple and many other PC companies fuelled the market and today, these companies are still striving to reduce the size and price of computer Hardware while improving its capacity.
Computer hardware has transformed in the last few decades as computers evolved from bulky, beige monsters to sleek and sexy machines. Computer Hardware – a History The dictionary defines ‘computer’ as any programmable electronic device that can store, retrieve, and process data. Computer Hardware evolved as data storage, calculation and data processing became important elements in work and life. In fact, the earliest computer Hardware is thought to be record keeping aids such as clay shapes that represented items in the real world – the early mechanics of merchants and accountants of the past. From the abacus and the slide rule came analogue and later, the electronic computer Hardware known today. A timeline of the history of computer Hardware: 1632 the first mechanical calculator was built by Wilhelm Schickard. It used cogs and gears and became the predecessor for computer Hardware. 1801 punched card technology began and by 1890 sorting machines were handling data, the first computer Hardware and installations used punched cards until the 1970s. 1820, Charles Xavier Thomas created the first mass-produced calculator. 1835, Charles Babbage described his analytical engine, which was the layout of a general-purpose programmable computer. 1909, Percy Ludgate designed a programmable mechanical computer. 1914, a central component in computer Hardware – the binary numeral system- was described by Leibniz. 1930s, desktop mechanical calculators, cash registers and accounting machines were introduced. By the 1960s, calculators advanced with integrated cuircuits and microprocessors. Digital computer Hardware replaced analogue computers. Digital computer Hardware The era of the computer as we know it today began with developments during the Second World War as researchers and scientists were spurred on by the military. 1960s and beyond ‘Third generation’ computer Hardware took off post 1960 thanks to the invention of the integrated circuit or microchip. This led to the microprocessor which in turn led to the microcomputer – computer Hardware that could be owned by individuals and small businesses. Steve Wozniak co-founded Apple Computer and is credited with developing the first mass market computer, although the KIM-1 and Altair 8800 came first. Evolution in computer Hardware After the 1970s the personal computer and evolution in computer Hardware exploded across the western world. Microsoft, Apple and many other PC companies fuelled the market and today, these companies are still striving to reduce the size and price of computer Hardware while improving its capacity.
Sunday, November 23, 2008
Sunday, November 9, 2008
History of the Memory of computers
The component that stores data to be accessed in any order is called a random access memory(RAM). it is considered as the main memory or primary storage. It is the working area used for displaying and manipulating data. It is usually in the form of integrated circuits called memory sticks or RAM sticks. The contents of RAM are erased when a computer is shut down. Semiconductor memory is computer memory we are all familiar with, computer memory on a integrated circuit or chip. Referered to as random-access memory or RAM, it allowed data to be accessed randomly, not just in the sequence it was recorded.
Dynamic random access memory (DRAM) is the most common kind of random access memory (RAM) for personal computers. The data the DRAM chip holds has to be periodicaly refreshed. Static random access memory or SRAM doesn't need to be refreshed.
Timeline of Computer Memory
1834 Charles Babbage begins build his "Analytical Engine", precursor to the computer. It uses read-only memory in the form of punch cards.
1932Gustav Tauschek invents drum memory in Austria.
1936 Konrad Zuse applies for a patent for his mechanical memory to be used in his computer. This computer memory is based on sliding metal parts.
1939Helmut Schreyer invents a prototype memory using neon lamps.
1942The Atanasoff-Berry Computer has 60 50-bit words of memory in the form of capacitors mounted on two revolving drums. For secondary memory it uses punch cards.
1947Frederick Viehe of Los Angeles, applies for a patent for an invention that uses magnetic core memory. Magnetic drum memory is independently invented by several people.
An Wang invented the magnetic pulse controlling device, the principle upon which magnetic core memory is based.
Kenneth Olsen invented vital computer components, best known for "Magnetic Core Memory" Patent No. 3,161,861 and as being the cofounder of Digital Equipment Corporation.
Jay Forrester Jay Forrester was a pioneer in early digital computer development and invented random-access, coincident-current magnetic storage.
1949Jay Forrester conceives the idea of magnetic core memory as it is to become commonly used, with a grid of wires used to address the cores. The first practical form manifests in 1952-53 and renders obsolete previous types of computer memory.
1950Ferranti Ltd. completes the first commercial computer with 256 40-bit words of main memory and 16K words of drum memory. Only eight were sold.
1951 Jay Forrester files a patent for matrix core memory.
1952The EDVAC computer is completed with 1024 44-bit words of ultrasonic memory. A core memory module is added to the ENIAC computer.
1955 AN WANG was issued U.S. patent #2,708,722 with 34 claims for magnetic memory core.
1966Hewlett-Packard releases their HP2116A real-time computer with 8K of memory. The newly formed Intel starts sell a semiconductor chip with 2,000 bits of memory.
1968 USPTO grants patent 3,387,286 to IBM's Robert Dennard for a one-transistor DRAM cell. DRAM stands for Dynamic RAM (Random Access Memory) or Dynamic Random Access Memory. DRAM will become the standard memory chip for personal computers replacing magnetic core memory.
1969Intel begin as chip designers and produce a 1 KB RAM chip, the largest memory chip todate. Intel soon switch to being notable designers of computer microprocessors.
1970Intel releases the 1103 chips, the first generally available DRAM memory chip.
1971Intel releases the 1101 chip, a 256-bit programmable memory, and the 1701 chip, a 256-byte erasable read-only memory (EROM).
1974Intel receives a U.S. patent for a "memory system for a multichip digital computer".
1975Personal consumer computer altair released, it uses Intel's 8-bit 8080 processor and includes 1 KB of memory. Later in the same year, Bob Marsh manufacturers the first Processor Technology's 4 kB memory boards for the Altair.
1984 apple computers releases the Macintosh personal compututer. It is the first computer that came with 128KB of memory. The one-megabyte memory chip is developed.
Dynamic random access memory (DRAM) is the most common kind of random access memory (RAM) for personal computers. The data the DRAM chip holds has to be periodicaly refreshed. Static random access memory or SRAM doesn't need to be refreshed.
Timeline of Computer Memory
1834 Charles Babbage begins build his "Analytical Engine", precursor to the computer. It uses read-only memory in the form of punch cards.
1932Gustav Tauschek invents drum memory in Austria.
1936 Konrad Zuse applies for a patent for his mechanical memory to be used in his computer. This computer memory is based on sliding metal parts.
1939Helmut Schreyer invents a prototype memory using neon lamps.
1942The Atanasoff-Berry Computer has 60 50-bit words of memory in the form of capacitors mounted on two revolving drums. For secondary memory it uses punch cards.
1947Frederick Viehe of Los Angeles, applies for a patent for an invention that uses magnetic core memory. Magnetic drum memory is independently invented by several people.
An Wang invented the magnetic pulse controlling device, the principle upon which magnetic core memory is based.
Kenneth Olsen invented vital computer components, best known for "Magnetic Core Memory" Patent No. 3,161,861 and as being the cofounder of Digital Equipment Corporation.
Jay Forrester Jay Forrester was a pioneer in early digital computer development and invented random-access, coincident-current magnetic storage.
1949Jay Forrester conceives the idea of magnetic core memory as it is to become commonly used, with a grid of wires used to address the cores. The first practical form manifests in 1952-53 and renders obsolete previous types of computer memory.
1950Ferranti Ltd. completes the first commercial computer with 256 40-bit words of main memory and 16K words of drum memory. Only eight were sold.
1951 Jay Forrester files a patent for matrix core memory.
1952The EDVAC computer is completed with 1024 44-bit words of ultrasonic memory. A core memory module is added to the ENIAC computer.
1955 AN WANG was issued U.S. patent #2,708,722 with 34 claims for magnetic memory core.
1966Hewlett-Packard releases their HP2116A real-time computer with 8K of memory. The newly formed Intel starts sell a semiconductor chip with 2,000 bits of memory.
1968 USPTO grants patent 3,387,286 to IBM's Robert Dennard for a one-transistor DRAM cell. DRAM stands for Dynamic RAM (Random Access Memory) or Dynamic Random Access Memory. DRAM will become the standard memory chip for personal computers replacing magnetic core memory.
1969Intel begin as chip designers and produce a 1 KB RAM chip, the largest memory chip todate. Intel soon switch to being notable designers of computer microprocessors.
1970Intel releases the 1103 chips, the first generally available DRAM memory chip.
1971Intel releases the 1101 chip, a 256-bit programmable memory, and the 1701 chip, a 256-byte erasable read-only memory (EROM).
1974Intel receives a U.S. patent for a "memory system for a multichip digital computer".
1975Personal consumer computer altair released, it uses Intel's 8-bit 8080 processor and includes 1 KB of memory. Later in the same year, Bob Marsh manufacturers the first Processor Technology's 4 kB memory boards for the Altair.
1984 apple computers releases the Macintosh personal compututer. It is the first computer that came with 128KB of memory. The one-megabyte memory chip is developed.
Subscribe to:
Posts (Atom)
