Computer Hardware
- 1. The hardware components are different kinds. Like – Input devices - accept data or commands in a form useable by computers Output devices display the processed information - printers, monitors, speakers. Processing devices in system unit and are comprised of circuitry. Storage devices - Drives read from and write to storage media i.e the physical material that can store data and programs. Communication devices provide connections between computers and communication networks, allowing for exchange of information and data with other computers via transmission media such as cables, telephone lines, and satellites Input / Output Devices – BIOS stands for Basic Input / Output System. •lowest-level software in the computer •Acts as an interface between the hardware (especially the chipset and processor) and the operating system. •The BIOS provides access to the system hardware and enables the creation of the higher-level operating systems that we use to run our applications. •The BIOS is also responsible for allowing to control computer's hardware settings, for booting up the machine when we turn on the power or hit the reset button, and various other system functions.
- 2. Input devices are Keyboard, Mouse, Joy stick, etc. Output devices gives us the processed results through printer, monitor, scanner etc. Processing Devices- The central Processing Unit - CPU
- 3. Register A register is one of a small set of data holding places that are part of a computer processor . A register may hold a computer instruction , a storage address, or any kind of data. Some instructions specify registers as part of the instruction. For example, an instruction may specify that the contents of two defined registers be added together and then placed in a specified register. A register must be large enough to hold an instruction - for example, in a 32-bit instruction computer, a register must be 32 bits in length. Depending on the processor design and language rules, registers may be numbered or have arbitrary names. program counter - A program counter is a register in a computer processor that contains the address (location) of the instruction being executed at the current time. stack pointer - A stack pointer is a small register that stores the address of the last program request in a stack. A stack is a specialized buffer which stores data from the top down. e-speak - E-speak is an open software platform designed by HP to facilitate the delivery of e-services (electronic services) over the Internet.
- 4. The System Unit The System Unit holds the central processing unit, memory modules, expansion slots, and electronic circuitry as well as expansion cards that are all attached to the motherboard; along with disk drives, a fan or fans to keep it cool, and the power supply. All other devices (monitor, keyboard, mouse, etc.), are linked either directly or indirectly into the system unit. The Motherboard The motherboard is the main circuit board of a computer. It contains the central processing unit (CPU), the Basic Input /Output System (BIOS), memory, mass storage interfaces, serial and parallel ports, expansion slots, and all the controllers for standard peripheral devices like the keyboard, disk drive and display screen. The chipset and other motherboard circuitry direct traffic and control the flow of information inside the computer. The chipset is a critical part of any computer to determine what sorts of features the computer can support. Storage devices MEMORY AND DATA Computers have two types of memory: ROM – Read Only Memory RAM - normal Read And Write Memory
- 5. Random Access Memory (RAM) • RAM is Primary Storage, also. Serves as computers workspace, storing all or part of the program that is being executed, as well as data being used by the program. Called internal storage. • RAM provides instructions and data to the CPU. These instructions/data are coded in bytes. Each byte is placed in a precise location in memory, called an address. To access data or instructions in memory, the computer references the addresses containing the bytes. The amount of memory available is therefore measured in bytes. Read Only Memory • ROM is nonvolatile. ROM chips contain permanently written data, called firmware. • ROM contains the programs that direct the computer to load the operating system and related files when the computer is powered on. • ROM chips are usually recorded when they are manufactured. PROM -Programmable Read Only memory chip cannot be changed to update or revise the program inside EPROM Erasable Programmable Read Only memory Data can be erased by high intensity UV light and chip can be reused . EEPROM Electrical Erasable Programmable Read Only memory under high voltage. FROM -Flash ROM is reprogrammable memory using normal voltage inside the PC.
- 6. • The amount of RAM needed depends on the types of applications you intend to run on the computer. S/w indicate the minimum amount of RAM required to run. • RAM chips consist of millions of switches that are sensitive to changes in electric current. • RAM chips are typically packaged on small circuit boards called memory modules, which are inserted into special slots on the motherboard. • RAM is Volatile storage: Power goes, data goes! Data/instructions are copied into memory as needed. On booting, operating system files are loaded from a storage device (the hard disk, usually) into RAM, and they remain there as long as your computer is running. • RAM contents changes as programs are executed. Two basic types of RAM are Dynamic RAM (DRAM), and Static RAM (SRAM). Most computers today use DRAM, which are also following types: SDRAM- Synchronous Dynamic RAM runs at the same pace as the system clock runs. DDR SDRAM- DDR stands for Double Data Rate - runs at double the pace the system clock runs - available in speeds from 266 MHZ up to 600MHZ DDR2 SDRAM runs at four times the pace the system clock runs - available in speeds from 400 MHZ up to 800MHZ
- 7. DDR SDRAM is a straightforward evolution from SDR SDRAM. The big difference between DDR SDRAM and SDR SDRAM is that - DDR reads data on both the rising and falling edges of the clock signal, so the DDR module can transfer data twice as fast as SDR SDRAM. While DDR has a limited clock rate, where as DDR2 to achieve speeds beyond of DDR, delivering bandwidth of 5.3 GB per second and beyond! Because DDR2 is able to operate with faster bus speeds, your memory doesn't hold back the performance of your processor. Motherboards are built to support only one type of memory. You cannot mix and match SDRAM, DDR, or DDR2 memory on the same motherboard in any system. They will not function and will not even fit in the same. Most desktops and notebooks use one of the three most popular types of synchronous dynamic random access memory (SDRAM) for the main system memory. Single data rate (SDR) SDRAM is the older type of memory.
- 8. Cache It is a small, high-speed memory area that is placed between the processor and the system memory. The value of the cache is that it is much faster than normal system memory. The most frequently used instructions are kept in cache memory so that the CPU can look in there first - allows the CPU to run faster because it doesn't have to take time to swap instructions in and out of main memory. Large, complex programs such as complex spreadsheets or database management programs benefit the most from having a cache memory available. Pentium II processors generally come with at least 512 KB of cache memory. Why is RAM so important? • Aside from the processor, the two most important factors affecting a PC's performance are RAM and hard disk capacity. • Hard disks are typically huge, so the primary limiting factor is the amount of installed RAM. • Without enough RAM, the operating system must swap out storage space with the hard disk. The OS creates a Paging File (swap file) to supplement RAM (workspace). This is Virtual Memory. • Virtual memory is inherently slow! RAM speed can typically be 120,000 times FASTER than the hard disk so the less you must rely on virtual memory, the faster your system will perform.
- 9. Process Flow When a letter is pressed on a keyboard, the electronic signals are converted into binary form and stored into memory. The computer then processes the data as bytes of information and converts them to the letters we see on the monitor screen or on a printed page. Non-Volatile Storage Devices • Disk drives • Internal & External Hard drives • Removable disk drives • Floppy disks (1.4 MB) • ZIP disks (100/250 MB) • (700MB), DVD-ROM (~5GB/side) •Read only (-ROM), write once (-R), re-writeable (-RW) •Combination drive •CD-RW/DVD-ROM, CD-RW/DVD-R Many other forms Memory Stick, Multi Media Card, Compact Flash, and Smart Media
- 11. Other Hardware Components • BUS It is consisting of about one hundred parallel wires; Some of these wires carry timing signals, others will have control signals, another group will have a bit pattern code that identifies the component that is to deal with the data, and other wires carry signals encoding the data . Signals are sent over the bus by setting voltages on the different wires (the voltages are small, like 0-volts and 1-volt). When a voltage is applied to a wire the effect propagates along that wire at close to the speed of light; Transmission of information is controlled by clocks that put timing signals on some of the wires. Information signals are encoded on to the bus, held for a few clock ticks to give all components a chance to recognize and if appropriate take action, then the signals are cleared. • Clocks Computers frequency clocks that control the internal operations of the CPU and the bus, there will be clocks that record the time of day and, possibly, serve as a form of "alarm clock" timer. The time of day clock will tick at about 60-times per second; at each tick, a counter gets incremented. An alarm clock time can be told to send a signal when a particular amount of time has elapsed. "Analog-to-Digital" (A-to-D) converters change external voltages ("analog" data) into bit patterns that represent numbers ("digital" data). A-to-Ds allow computers to work with all kinds of input. The input voltage can come from a photo- multiplier/detector system (allowing light intensities to be measured), or from a thermocouple (measurements of temperature), a pressure transducer, or anything else that can generate a voltage. This allows computers to monitor all kinds of external devices
- 12. • Different types of Ports These types of port designs are based on whether or not fast data transmission rates are required by the device or not. Most computers come with basic types of ports (serial, parallel, keyboard, mouse, and USB); and expansion cards allow you to expand the available types needed by specific devices. Serial Ports: Transmit data one bit at a time, Parallel ports : Transmit more than one byte at a time. Understanding the differences among connector types is useful and important, as the cable required to attach a device to your computer is specific to its connector, not to mention the port on the computer.
- 15. Computer Software It is a collection of computer programs and related data that provides the instructions for telling a computer what to do and how to do it. In other words, software is a set of programs, procedures, algorithms and its documentation concerned with the operation of a data processing system. Program software performs the function of the program it implements, either by directly providing instructions to the computer hardware or by serving as input to another piece of software. Computer hardware encompasses the physical interconnections and devices required to store and execute (or run) the software. Software are different types : • System Software • Application Software • Programming Software • System software is computer software designed to operate and control the computer hardware and to provide a platform for running application software. Device drivers such as computer BIOS and device firmware provide basic functionality to operate and control the hardware connected to or built into the computer.
- 16. For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between programs and the computer hardware. Operating systems Application software usually runs on an underlying software Operating systems can be found on almost any device that contains a computer—from cellular phones and video game consoles to supercomputers and web servers. Examples of popular modern operating systems include Android, BSD, IOS, Linux, Mac OS X, Microsoft Windows, Windows Phone, and IBM z/OS. All these, except Windows and z/OS, share roots in UNIX. An operating system (OS) is special type of system software that manages computer hardware resources and provides common services for computer programs. The operating system is a vital component of the system software in a computer system. Application programs require an operating system to function. The operating system allows the parts of a computer to work together by performing tasks like transferring data between memory and disks or rendering output onto a display device. It also provides a platform to run high-level system software and application software.
- 17. Application Software It is also known as an application or an app, is computer software designed to help the user to perform specific tasks. Such as, enterprise software, accounting software, office suites, graphics software and media players. Application software is developed to perform in any task that benefits from computation. It is a set of programs that allows the computer to perform a specific data processing job for the user. It is a broad category, and encompasses software of many kinds, including the internet browser being used to display this page. Many application programs deal principally with documents. Apps may be bundled with the computer and its system software, or may be published separately. Application software is contrasted with system software, which manage and integrate a computer's capabilities, but typically do not directly apply in the performance of tasks that benefit the user. The system software serves the application, which in turn serves the user. Application software applies the power of a particular computing platform or system software to a particular purpose.
- 18. Firmware is the combination of persistent memory and program code and data stored in it. Devices containing firmware are embedded systems (such as traffic lights, consumer appliances, and digital watches), computers, computer peripherals, mobile phones, and digital cameras. The firmware contained in these devices provides the control program for the device. Firmware is held in non-volatile memory devices such as ROM, EPROM, or flash memory. Changing the firmware of a device may rarely or never be done during its economic lifetime; some firmware memory devices are permanently installed and cannot be changed after manufacture. Common reasons for updating firmware include fixing bugs or adding features to the device. This may require physically changing ROM integrated circuits, or reprogramming flash memory with a special procedure. Firmware such as the ROM BIOS of a personal computer may contain only elementary basic functions of a device and may only provide services to higher-level software. Firmware such as the program of an embedded system may be the only program that will run on the system and provide all of its functions.
- 19. A programming software is a program or application that software developers use to create, debug, maintain, or otherwise support other programs and applications. The term usually refers to relatively simple programs, such as compilers, debuggers, interpreters, linkers, and text editors, that can be combined together to accomplish a task. Programming tools are intended to assist a programmer in writing computer programs, and they may be combined in an integrated development environment (IDE) to more easily manage all of these functions. Programming software is a sub-category of system software but sometimes it is stated as a separate category of software along with application and system software. Programming Software Other Related Topics of Software • Documentation Most software has software documentation so that the end user can understand the program, what it does, and how to use it. Without clear documentation, software can be hard to use.
- 20. • Library Software libraries include collections of functions and functionality that may be embedded in other applications. Operating systems include many standard Software libraries, and applications are often distributed with their own libraries. • Standard Since software can be designed using many different programming languages and in many different operating systems and operating environments, software standard is needed so that different software can understand and exchange information between each other. For instance, an email sent from a Microsoft Outlook should be readable from Yahoo! Mail and vice versa. • Execution Computer software has to be "loaded" into the computer's storage. Once the software has loaded, the computer is able to execute the software. This involves passing instructions from the application software, through the system software, to the hardware which ultimately receives the instruction as machine code. Each instruction causes the computer to carry out an operation – moving data, carrying out a computation, or altering the control flow of instructions. •Quality and reliability Software quality is very important, especially for commercial and system software like Microsoft Office, Microsoft Windows and Linux. If software is faulty (buggy), it can delete a person's work, crash the computer and do other unexpected things. Faults and errors are called "bugs." Many bugs are discovered and eliminated (debugged) through software testing
- 21. • License The software's license gives the user the right to use the software in the licensed environment. Some software comes with the license when purchased off the shelf. Other software comes with a free software license, granting the recipient the rights to modify and redistribute the software. • Patents Software can be patented in some but not all countries; however, software patents can be controversial in the software industry with many people holding different views about it. The controversy over software patents is about specific algorithms or techniques that the software contains, which may not be duplicated by others and considered intellectual property and copyright infringement depending on the severity. • Design and implementation Design and implementation of software varies depending on the complexity of the software. For instance, design and creation of MS Word software will take much more time than designing and developing MS Notepad because of the difference in functionalities in each one.