Honest Tom's A+ Hardware Notes
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Central Processor Unit (CPU)
- The math coprocessor deals with floating-point numeric operations.
- Protected mode is a processor feature that allows 2 or more programs run without interfering with one-another.
- Superscaler - Two chips inside: one for parallel processing and the other for fault tolerance.
- Instructions / clock cycle - 4 instructions, 2 on each path.
- Intel Pentium 2 (166-400 MHz)
- Intel Pentium 3 (400MHz – 1.2GHz)
- Intel Pentium 4 (1.4 - 3.4 GHz)
- Intel Celeron (1.7 - 3.2 GHz)
- Celeron D (to 3.2 GHz)
- Intel Pentium 4 Extreme Edition (3.2, 3.4 GHz)
Cache:
- L1 and L3 - Internal Cache
- L2 - External Cache on board, Northbridge. Part of Front Side Bus (FSB) – “the golden triangle”
- Southbridge looks after AGP and PCI slots
- FSB – CPU, RAM, Northbridge
CPU Connectivity:
- Socket 7 – Earlier Pentium CPUs ZIF contact connector
- Socket 8 - Pentium Pro 387-pin
- Slot 1 - Pentium II 242 SEC contact connector
- Slot A - AMD processor, same with Socket A.
- ZIF Socket - Zero Insertion Force
- Socket 370 - Pentium III and Celeron - Front Bus Frequencies: 66, 100 and 133 MHz
- Socket 423 - Pentium IV (OLGA) - Front Bus Speed: 100 MHz FSB
- Socket 478 - Pentium IV (FC-PGA2)- Front Bus Frequencies: 400 MHz - 800 MHz (100 MHz - 200 MHz QDR)
- LGA - Land Grid Array - 775 Balls.
Sockets:
• Socket 1 - 169 pin holes PGA LIF socket.
• Socket 2 - 238 pin holes PGA ZIF socket.
• Slot 1 - 242 leads. SEC slot.
• Slot 2 - 330 leads. SEC slot.
• Socket 370 - 370 pin holes SPGA ZIF socket.
• Socket 418 - 418 pin holes SPGA ZIF socket, this socket was never released.
• Slot A - 242 leads. SEC slot.
• Socket A - 462 (actually 453) pin holes ZIF socket.
• Socket 423 - 423 pin holes SPGA ZIF socket.
• Socket 478 - 478 pin holes FC-PGA2 ZIF socket.
…………
• Socket T - 775 balls (30x33) FC-LGA4 socket.
• Socket 775 - 775 balls (30x33) FC-LGA6 socket.
• Socket 603 - 603 pin holes (31x25) µPGA ZIF socket.
• Socket 604 - 604 pin holes (31x25) µPGA ZIF socket. For faster bus speeds and Low Voltage Xeons.
• PAC418 - 418 pin holes (2x(19x6)) VLIF socket.
• PAC611 - 611 pin holes (25x28) VLIF socket.
• Socket 754 - 754 pin holes (29x29) µPGA ZIF socket.
• Socket 940 - 940 pin holes (31x31) µPGA ZIF socket.
• Socket AM2 - 940 pin holes (31x31) µPGA ZIF socket.
Memory
ROM (Read-Only Memory):
- ROM is a form of non-volatile memory.
- Contains both POST and SETUP.
RAM (Random Access Memory):
- RAM is volatile memory and does not retain data without power.
- RAM contains any active application, including the operating system.
NVRAM (Non-Volatile Memory):
- Can maintain data without the use of power.
HMA (or high memory area) is the first 64K of extended memory.
VRAM – Video RAM
- Conventional memory is the first 640K of memory.
- Upper memory is the memory between 640K and 1024K.
- UMA used to load DOS drivers to allow applications more conventional memory.
- Extended memory is the memory above 1024K.
- Expanded memory is addressed in pages of 16K.
General DRAM packaging formats
- DRAM chip (Integrated Circuit or IC)
- Dual in-line Package (DIP)
- DRAM (memory) modules
- Single In-line Pin Package (SIPP)
- Single In-line Memory Module (SIMM)
- Dual In-line Memory Module (DIMM)
- Rambus In-line Memory Module (RIMM), technically DIMMs but called RIMMs due to their proprietary slot.
- Small outline DIMM (SO-DIMM). Smaller version of the DIMM, used in laptops. Comes in - 72 pins (32-bit), 144 pins (64-bit) and 200 pins (72-bit) .
- Small outline RIMM (SO-RIMM). Smaller version of the RIMM, used in laptops.
- Stacked RAM chips use two RAM wafers that are stacked on top of each other. This allows a large module (eg:512mb or 1Gig SO-DIMM) manufactured using cheaper low density wafers. Stacked chips draw more power.
- DIP 18-pin (DRAM chip, usually pre-FPRAM)
- SIPP (usually FPRAM)
- SIMM 30-pin (usually FPRAM)
- SIMM 72-pin (so-called "PS/2 SIMM", usually EDO RAM)
- DIMM 168-pin (SDRAM)
- DIMM 184-pin (DDR SDRAM)
- DIMM 240-pin (DDR2 SDRAM)
Power Settings:
S1 is the simplest energy-saving state, often used in older systems whose drivers or hardware won't behave well with more sophisticated levels of power management. A system at the S1 power level simply shuts down the hard drive(s) and monitor, but leaves everything else running normally. Different vendors call S1 by different names, but sleep or standby are perhaps the most common.
S2 offers greater power savings because it not only powers down the monitor and drives, it also cuts power to the CPU and its cache. Confusingly, this level also is sometimes called sleep or standby.
S3 is a deeper power-savings mode that shuts down almost everything except for the barest trickle of power needed to keep the contents of RAM from fading away and to listen for a wake-up action. In a way, you can think of S3 as a "suspend to RAM" state. In fact, many vendors do refer to S3 as "suspend" mode, but others may call it standby, sleep, instant on, on now, and the like.
S4 is fundamentally different from levels S1 to S3. It's hibernation, where the system stops all activity, just as if you had shut it off. But S4 is also different from the simple power-off of level S5 because, before powering down, the S4 hibernation system writes the contents of RAM and some CPU settings to a special file on your hard drive (often called something like "hiberfil.sys").
All these power states are defined in the industry-standard Advanced Configuration and Power Interface specification, developed by Compaq, Intel, Microsoft, Phoenix, and Toshiba.
PC Ports
Parallel ports:
- 25 Pin female, "D" connector (IEEE-1284 cable)
- Sends and receives 8 bits of data at a time
Serial ports:
- 25 Pin male, "D" connector or 9 Pin male, "D" connector
- Sends and receives 1 bit of data at a time
Video:
- HDA 15 pin female, 3 rows of pins.
-XGA
Cables and Connectors
- Tape, removable, hard, and optical drives along with scanners can all use SCSI connections.
- Up to seven devices can be chained off of a SCSI port.
- 18 feet is the maximum length that a SCSI-1 cable can support.
- Most external SCSI devices have 50,68, 84 pin female ports.
- Most Controller Cards are set to SCSI ID 7.
- Null modem cables (serial cables) are used to transmit data between 2 DTE devices.
- 15 feet (3m) is the maximum length that a serial (RS-232) cable should be.
- Phone lines (few network) cables use RJ11 connectors. Connector resembles a small phone jack.
- Twisted pair cables use RJ45 connectors. Connector resembles a fat phone jack.
COM Ports
- COM1 and COM3 use IRQ4.
- COM2 and COM4 use IRQ3.
- The majority of PC's have only 2 COM port connectors.
Monitors
Dot pitch is the space between pixels in millimeters.
The refresh rate is the number times display is redrawn every second.
Ratio 4:3
SVGA 1024 x 768
Video Cards
AGP 1x - A 32-bit channel operating at 66 MHz resulting in a maximum data rate of 266 megabytes per second (MB/s), doubled from the 133 MB/s transfer rate of PCI bus 33 MHz / 32-bit; 3.3 V signaling.
AGP 2x - A 32-bit channel operating at 66 MHz double pumped to an effective 133 MHz resulting in a maximum data rate of 533 MB/s; signaling voltages the same as AGP 1x;
AGP 4x - A 32-bit channel operating at 66 MHz quad pumped to an effective 266 MHz resulting in a maximum data rate of 1066 MB/s (1 GB/s); 1.5 V signaling;
AGP 8x - A 32-bit channel operating at 66 MHz, strobing eight times per clock, delivering an effective 533 MHz resulting in a maximum data rate of 2133 MB/s (2 GB/s); 0.8 V signaling.
PCI Express - Abbreviated officially with PCIe (PCI-E is also often used) and should not be mistaken for PCI-X, is an implementation of the PCI connection standard that uses existing PCI programming concepts, but bases it on a completely different and much faster full duplex, multi-lane, point to point serial physical-layer communications protocol. PCI Express was formerly known as Arapaho or 3GIO for 3rd Generation I/O.
- PCIe transfers data at 250 MB/s per lane. With a maximum of 32 lanes, PCIe allows for a total combined transfer rate of 8 GB/s.[1] To put these figures into perspective, a single lane has nearly twice the data rate of normal PCI, a four lane slot has a comparable data rate to the fastest version of PCI-X, and an eight lane slot has a data rate comparable to the fastest version of AGP. The full duplex point to point nature of PCIe should further improve its advantage over PCI, particularly in systems with many devices.
PCI-X (Peripheral Component Interconnect Extended) is a computer bus and expansion card standard designed to supersede PCI. It is essentially a faster version of PCI, running at twice the speed, and is otherwise similar in physical implementation and basic design. It has itself been replaced in modern designs by the similar-sounding PCI Express, which features a very different logical design.
- PCI-X was developed jointly by IBM, HP, and Compaq. PCI-X is a revision to the PCI standard that doubles the clock speed (from 66 MHz to 133 MHz) and hence the amount of data exchanged between the computer processor and peripherals. Standard PCI supports up to 64-bit at 66 MHz (though anything above 32-bit at 33 MHz is only seen in high end systems) and additional bus standards move 32 bits at 66 MHz or 64 bits at 33 MHz
IRQ (Interrupt Requests)
IRQ 1 Keyboard
IRQ 2(9) Video Card
IRQ 3 Com2, Com4
IRQ 4 Com1, Com3
IRQ 5 Available (Normally LPT2 or sound card)
IRQ 6 Floppy Disk Controller
IRQ 7 Parallel Port (LPT1)
IRQ 8 Real-time clock
IRQ 9 Redirected IRQ2
IRQ 10 Available
IRQ 11 Available
IRQ 12 PS/2 Mouse
IRQ 13 Math Coprocessor
IRQ 14 Hard Disk Controller
IRQ 15 Available
I/O Ports
COM1 3F8H
COM2 2F8H
COM3 3E8H
COM4 2E8H
LPT1 378H
LPT2 278H
Drives
- A cluster is a group of sectors. Sectors are aligned in tracks and shown as pie shaped.
- The seek time is the time that is takes the head to reach the needed track.
- The latency period is the time that it takes the sector to move under the head.
-The access time is the overall time it takes a hard drive to find data.
- The data transfer rate is how fast the hard drive sends data to the PC.
- FORMAT /S is the fastest way to make a bootable disk. The /S switch tells FORMAT to copy system boot files.
- FDD (Floppy Disk Controllers) controllers use DMA channel 2 in most cases, First DMA available is 4.
- HDI = Head to Disk Interference
- CD, CD-ROM, DVD: Read only storage, WORM, used for mass distribution of digital information
- CD-R, DVD-R, DVD+R: Write once unique storage, used for tertiary and off-line storage
- CD-RW, DVD-RW, DVD+RW, DVD-RAM: Rewritable disks. The +/- indicates DVD can operate both standards.
- Blu-ray - blue-violet laser used to read and write a shorter wavelength (405 nm) 25GB vs DVD 4.7GB.
- HD DVD - 15GB and dual 30GB.
Laser wavelength / 405 Nm / 405 Nm / 650 Nm / 650 Nm
Numerical aperture / 0.85 / 0.65 / 0.6 / 0.6
Storage capacity single layer / 25 GB / 15 GB / 4.7 GB / 4.7 GB
Storage capacity dual layer / 50 GB / 30 GB / 8.5 GB / 8.5 GB
Playback time on two layers (Standard Definition) / 23 hours / 13.8 hours / N/A / 4 hours
Playback time on two layers (High Definition) / 9 hours / 5.4 hours / 2 hours / -
Maximum data transfer rate / 54.0 Mbit/s / 36.55 Mbit/s / 36.55 Mbit/s / 11.08 Mbit/s
Networking
- Coaxial, twisted pair, and fiber optic cables are all used in networking.
- A token ring network passes packets of data called tokens to each station in a network.
- LAN - Local Area Network WAN - Wide Area Network MAN - Metropolitan Area Network
- Fiber-Optic - Cables designed for high transfer rates over large distances; carry light pulse
signals through glass core at speeds of between 100Mbps - 200,000Mbps.
- Ethernet use coaxial and twisted pair wiring, and can support speeds of 10mbps -100mpbs.
- 10Base5 - 10 Mbps transfer rate with coaxial wire.
- 10BaseT - 10 Mbps transfer rate, baseband transmission, with twisted pair wire.
- 100BaseT - 100 Mbps transfer rate, baseband transmission, with twisted pair wire.
- 100BaseTX – Two Pairs of Wires, 100BaseT4 – Four pairs of wires or Eight in total.
- 100BaseFL – Fiber Optic.
Printers
Laser Printers:
The order of processes in a laser printer is: Crystal Clear Water Doesn’t Taste Funny
1. Cleaning 2. Charging 3. Writing 4. Developing 5. Transferring 6. Fusing
The primary corona has the highest negative charge in a printer.