Binary to Decimal Conversion, Bus Speed, Memory Types, and PC Components
Binary to Decimal Conversion
Here’s how to convert binary numbers to decimal:
- List the powers of two from right to left. Start with the number 1 (which is 20). Increment the exponent by one for each subsequent power. Stop when the number of elements in the list equals the number of digits in the binary number.
- Write down the corresponding power of two only if the binary digit is a 1.
- Add all the numbers from step 2 to get the decimal equivalent.
Bus Speed and Bus Width
- Bus Speed: This is the number of bits or bytes that the bus transmits in a unit of time (typically a second). For example, a 100 Mbps bus sends 100 megabits of data per second.
- Bus Width: This refers to the size of the data that the bus transmits in a single cycle. For instance, a 32-bit computer uses 32 wires for data transmission.
Memory Types: DRAM, SRAM, and Error Detection
- DRAM (Dynamic Random Access Memory): This memory chip serves as the main memory. DRAM requires constant refreshing with electrical pulses to retain stored data.
- SRAM (Static Random Access Memory): This memory chip is used for cache memory. SRAM is significantly faster than DRAM and doesn’t need to be refreshed as frequently.
- Nonparity: This method cannot detect data corruption.
- Parity: This method uses 8 bits for data and 1 bit for error checking (the parity bit). Typically, odd parity is used, meaning the total number of 1s in the data byte, including the parity bit, should be odd. This allows for the detection of single-bit errors. If the output is even, it indicates data corruption. However, this system cannot detect multiple errors.
- Error Correction Code (ECC): ECC, either as a technology (Error Checking and Correction) or software (Error Correction Code), employs logarithms to detect and correct data corruption. While it can correct single-bit errors, it cannot handle multiple errors. ECC is more reliable than parity but not necessarily faster.
Peripheral Component Interconnect (PCI)
PCI has two voltage signal levels and is keyed for different voltages. This keying allows you to determine the voltage level. Similarly, the size of the connector indicates whether it’s a 32-bit or 64-bit slot.
Accelerated Graphics Port (AGP)
AGP is a bus designed for connecting peripheral devices to the computer’s motherboard. AGP buses operate at various frequencies and voltages, exhibiting more differences than PCI. It was developed to address the bottleneck encountered by graphics cards when using the PCI bus. The AGP bus is exclusively used for connecting graphics cards.
PCI Express (PCIe)
PCIe is considerably faster than both PCI and AGP. Instead of buses, it utilizes unidirectional serial lanes. Each expansion slot uses one, two, four, eight, sixteen, or thirty-two data links between the motherboard and connected cards, denoted as x1, x2, x4, x8, x16, and x32.
Northbridge and Southbridge
Northbridge
The Northbridge is directly connected to the microprocessor and manages data flow between all components and the microprocessor. Due to its high speed, all high-speed components are connected to it. The AGP port is also directly connected to the Northbridge because it needs to be close to the RAM. The same applies to PCI Express. It is located near the fan and includes a heat sink, as it tends to generate significant heat. It is commonly used for video cards.
Southbridge
In contrast to the Northbridge, the Southbridge is slower and generates less heat. It incorporates various controller functions and oversees data transfer to and from the hard disk. It is situated near the PCI slots and is used to connect peripheral devices such as LAN cards, sound cards, modems, network interfaces, and FireWire.