Computer Hardware: Connectors, Buses, Memory, Peripherals
Connectors and Buses
Connectors link external peripherals like the mouse, printer, etc., to the computer.
The electrical connector is responsible for powering the motherboard from the power supply. It also powers the hard disk drive, CD-ROM drives, and other storage and control systems.
Buses are sets of parallel electrical conductors that interconnect the various elements of a computer. We can distinguish between:
- Data Buses
- Address Buses (Implied, though ‘Management’ was used)
- Control Buses
It’s important to differentiate between the internal bus, which is within the processor, and the external bus, used to connect distinct hardware elements.
Memory Explained
The purpose of memory is to receive information (data and software), provide storage for it, and allow later retrieval. The total memory capacity is an essential factor in gauging a computer’s power.
Memory capacity is usually expressed in kilobytes (KB), megabytes (MB), gigabytes (GB), and even terabytes (TB).
RAM (Random Access Memory)
RAM allows access to any of its data at any time, permitting both reading and writing. It refers to the memory available on the motherboard, which is composed almost entirely of RAM. It provides temporary storage that can be written to and erased. There are two basic types:
- DRAM (Dynamic Random Access Memory)
- SRAM (Static Random Access Memory)
ROM (Read-Only Memory)
ROM is responsible for storing system configuration data. It is non-volatile memory, meaning information can be stored indefinitely even if power is disconnected. It contains software engraved irreversibly, so it cannot be easily modified or destroyed. The computer reads the program in ROM and executes it but cannot typically expand or modify it.
For specific applications, variations are used:
- PROM (Programmable Read-Only Memory): Delivered blank to the user to program content based on their needs.
- EPROM (Erasable Programmable Read-Only Memory): Reprogrammable memory (usually via UV light).
- EEPROM/EAPROM (Electrically Erasable/Alterable Programmable Read-Only Memory): Electrically alterable memory.
- Cache Memory: Positioned between the processor and main memory to accelerate the latter’s performance.
- VRAM (Video RAM): Located on the video card; it receives information and sends it to the monitor.
Peripherals Detailed
Peripherals are devices attached to the computer that allow it to receive input data, issue output, and store data.
Classification by Location
- External: Outside the computer case (e.g., keyboard, monitor).
- Internal: Located inside the computer case (e.g., CD-ROM drive, internal hard drive).
Classification by Function
- Input Devices: Responsible for entering information (programs or data) into the processor. These peripherals capture data and transfer it to the computer in a language it understands (e.g., mouse, keyboard, scanner, light pen).
- Output Devices: Provide the results from the processor, transferring data from the processor to the outside. They take data and present it externally in a language understandable to the user (e.g., printer, speakers, monitor).
- Storage Devices: Used for storing data; they function as both input and output devices (e.g., floppy disks, CD-ROMs, hard disks, USB drives).
Printers Overview
Impact Printers
- Daisy Wheel: Produces good quality text (similar to a typewriter) but is slow and cannot print graphics. (Note: ‘Margarita’ likely referred to Daisy Wheel)
- Dot Matrix: Quality varies depending on the number of pins (heads); more pins mean better characters, but they generate significant noise. Can produce carbon copies.
Non-Impact Printers
- Inkjet: Offers good quality and relatively fast printing. Effective for color.
- Laser: Produces high-quality text and graphics quickly. Toner (ink) fuses easily (dries fast), but cartridges can be expensive.