Lesson 4
Note: 32-bit Pentium compatible CPUs feature additional larger registers for floating point calculations (80-bit) and SIMD processing (64- or 128-bit). They also feature a 64-bit data bus. It is the GP register size that makes a CPU 32- or 64-bit.
This platform (IA-64) has never gained acceptance in the PC market, however. AMD's 64-bit instruction set (AMD64) has proved more popular and was adopted by Intel for its 64-bit desktop and mobile line. Intel refers to it as EM64T or Intel 64. The same instruction set is also called x86-64 or x64.
Molex and SATA connectors.
The 4-pin (1x4) Molex connectors and 15-pin (1x15) SATA (Serial ATA) connectors supply +12 V and +5 V power for peripheral devices housed within the system case. If there are insufficient adapters, it is possible to obtain splitters (also called y-adapters) so that two devices can be connected to the same cable.
P4 and EPS 12V connectors.
The ATX12V standard specifies an additional 4-pin (2x2) +12 V connector (often labeled P4) to support the operation of the CPU.
Secure boot
is a security system offered by UEFI. It is designed to prevent a computer from being hijacked by malware. Under secure boot, UEFI is configured with digital certificates from valid OS vendors. The system firmware checks the operating system boot loader using the stored certificate to ensure that it has been digitally signed by the OS vendor. This prevents a boot loader that has been modified by malware (or an OS installed without authorization) from being used.
input voltage.
This is if you are taking a computer to another country. For example, A PSU designed only for use in North America, with an input voltage of 115 V, will not work in the UK, where the voltage is 240 V. Some PSUs are dual voltage and are auto-switching (or auto-sensing); some have a switch to select the correct voltage; others can only accept one type of input voltage (fixed).
Cache
is a small block of high-speed memory that enhances performance by pre-loading (caching) code and data, cache stores instructions and data that the CPU is using regularly. Cache is designed in multiple levels. Level 1 cache is "closest" to the CPU and supports the fastest access. Level 2 cache is typically larger and a bit slower while Level 3 and Level 4 cache, if used, are larger and possibly a bit slower still.
passive cooling device
this is what a heat sink is, means that it does not require extra energy (electricity) to work.
whats Light Emitting Diode (LED)
used to indicate that the device is switched on and receiving power hard drive LED shows activity; normally this should flicker periodically. If a hard drive LED is solid for extended periods it can indicate a problem, especially if the PC is not doing any obvious processing. network adapters often have LEDs to indicate the connection speed and activity on the network.
heat spreader
uses the same design but is a flat container rather than a pipe. This design is better suited to portable computers. If used without fans, heat pipes and spreaders are classed as passive cooling
What is alternating current (AC)?
which means that the current flows in both directions around the circuit and the voltage alternates between low and high values. AC is a cheap way to distribute electrical power over long distances, but is incompatible with PC electronics. Transformers in the PC's power supply are used to convert AC to DC voltages.
three options for securing access to the disk specifically (rather than the PC generally):
• Configure and store the password in the PC firmware; this means that the disk is unusable except with the designated computer. • Store the password in the disk firmware; this is configured in conjunction with a compatible PC firmware and means that the disk is transferable between computers with a compatible firmware. • Use Full Disk Encryption (FDE) to encode the contents of the drive as well as password-protecting it. The selected password is used as the basis of the encryption key. Again, this requires a hard drive and firmware compatible with the same FDE product.
To troubleshoot, try the following tests and solutions:
• Ask what has changed—if the system firmware has been flashed and the PC has not booted since, the system firmware update may have failed. Use the reset procedure. • Check cabling and connections, especially if maintenance work has just been performed on the PC. An incorrectly oriented storage adapter cable or a badly seated adapter card can stop the POST from running. Correct any errors, reset adapter cards, and then reboot the PC. • Check for faulty interfaces and devices—it is possible that a faulty adapter card or device is halting the POST. Try removing one device at a time to see if this solves the problem (or remove all non-essential devices then add them back one-by-one). • Check the PSU—even though the fans are receiving power, there may be a fault that is preventing the Power Good signal from being sent to the CPU, preventing POST. • Check for a faulty CPU or system firmware. If possible, replace the CPU chip with a known good one or update the system firmware. • Some motherboards have jumpers to configure modes (such as firmware recovery) or processor settings. If the jumpers are set incorrectly it could cause the computer not to boot. If a computer will not work after being serviced, check that the jumpers have not been changed.
To isolate the cause of no power, try the following tests:
• Check that other equipment in the area is working; there may be a blackout. • Check that the PSU cabling is connected to the PC and the wall socket correctly and that all switches are in the "on" position. • Try another power cable—there may be a problem with the plug or fuse. Check that all of the wires are connected to the correct terminals in the plug. Check the fuse resistance with a multimeter. • Try plugging another piece of "known-good" equipment (such as a lamp) into the wall socket. If it does not work, the wall socket is faulty. Use another socket and get an electrician to investigate the fault. • Try disconnecting extra devices, such as optical drives. If this solves the problem, the PSU is underpowered and you need to fit one with a higher power rating.
When you are trying to find basic hardware problems look for simple solutions first like:
• Find out if anything has changed. • Eliminate hardware issues as a cause first. • Try one thing at a time. • Take care to ensure that a user's data is backed up before proceeding.
What are the electrical components used in a PC's electronic circuits?
• Conductor—a material that is good at conducting electricity, such as gold, copper, or tin. These are used for wires and contacts. • Insulator—a material that does not conduct electricity, such as rubber or plastic. These are used as sheaths for wires to prevent short circuits or electric shocks. • Semiconductor—a material that can act as both a conductor and an insulator. This provides switch-like functionality, where a circuit can be opened and closed, used to represent binary (on/off) digits. • Resistor—these oppose the flow of current without blocking it completely and are used to manage electronic circuits. • Diode—a valve, allowing current to flow in one direction only. These are used in a computer's power supply and as protection for components. • Fuse—this is a safety device. The flow of electricity creates heat. A fuse is designed so that if the current is too high, the heat will cause the fuse wire to melt and break, breaking the circuit and shutting off the current. • Transistor—in computers, these are semiconductor switches used to create logic devices. Typically, a type called a Field Effect Transistor (FET) is used to make components such as CPUs and memory. • Capacitor—this stores electrical energy and is often used to regulate voltages. Note that a capacitor can hold a charge after the power is removed.
There are usually at least two passwords, though some systems may allow for more:
•Supervisor/Administrator/Setup—protect access to the system setup program. •User/System—lock access to the whole computer. This is a very secure way of protecting an entire PC as nothing can be done until the POST has taken place. The only real way of getting around this would be to open the PC and reset the system setup configuration, which isn't very easy to do. Note: For user/system authentication, you have to tell everyone who uses the PC the password, which weakens the security considerably. This option would be used only on workstations and servers that aren't used for interactive logon (a computer running monitoring or management software, for instance).
Some laptop firmware is bundled with LoJack tracking software
(developed by Absolute Software), essentially a security rootkit designed to prevent theft. If enabled (and the user has subscribed to LoJack®), a "dialer" is activated that attempts to contact Absolute Software's authorization servers each day. If the laptop is reported stolen, the authorization servers can force the laptop into a locked down mode (require a boot password or remotely wipe data, for instance). The software can also attempt to locate the laptop, either using GPS data if the laptop has a GPS chip or using information about nearby wireless networks. It can also try to identify the thief by installing forensic tools (a key logger and screen capture utility).
what does 1, 2, none, continuos beeping, repeating short beeps, 1 long 1 short beep, 1 long, 2 or 3 short beeps, 3 long beeps mean?
1 short beep = Normal POST—system is OK. 2 short beep = POST error—error code shown on screen. no beeps = Power supply or motherboard problem (use a multimeter to check the onboard speaker is functioning). Continuous beep = Power supply, motherboard, or system memory problem. repeating short beeps = Power supply, motherboard, or keyboard problem. 1 long 1 short beep = Motherboard problem. 1 long, 2 or 3 short beeps = Display adapter error. 3 long beeps = 3270 keyboard card.
How to update system firmare
1. Access the system firmware setup program. 2. Record any custom system setup settings. Updating the firmware may reset the system configuration to the default, so you will need to change the system settings back after the update. 3. Download the upgrade program from the website to your computer. 4. If the files are in a zip archive, extract them. 5. If there is an option to back up the existing firmware configuration, use it. 6. If necessary, adjust the jumper on the motherboard to allow system firmware upgrades to take place. 7. Ensure that you have an up-to-date data and system backup in case the firmware upgrade goes wrong. 8. Ensure the power supply is reliable. Connect a laptop to AC power rather than using the battery and (ideally) use an Uninterruptible Power Supply. 9. Run the update. There are usually two or three options for running the firmware update, including: • Start the system setup utility and look for the option to update the system firmware. You can then navigate to the folder where you saved the update and run it, or you may need to copy the file to a USB stick and run it from there. • Run the update utility from Windows. Using a Windows utility is relatively risky. Before running it, close all other software programs and disable antivirus scanners. You must minimize the risk of another process causing a lockup during the firmware update. 10. If a firmware update goes wrong (for example, if there is a power cut during the flashing process), you may be able to re-install the old firmware from a backup. However, it is equally likely that the component will be unusable. If this is the case, you will have to contact the manufacturer for help or buy a new one. Note: In the case of failed motherboard updates, the motherboard may feature a recovery mode jumper. You may also need to remove the RTC battery.
what is the general process for a POST
1. The POST starts by locating video card firmware at the address C000 in memory. If found, the video card is initialized from its own firmware. Information from the card manufacturer may also be displayed at this point. 2. A startup screen is displayed. More tests on the system, including counting through system RAM, are performed. If any errors are found, a text error message is displayed. Explanations of these messages are usually found in the system guide. Once numeric codes, these messages now tend to be descriptive, such as "key stuck." 3. You should be able to access the system setup routine from this point. This allows you to reconfigure the settings stored in system setup. The key used to invoke system setup varies according to the firmware, but is usually Delete, F2, Esc, F10, or F1. 4. Some PCs indicate that system checks have been successfully completed at this point with a single short beep, but the trend for modern computers is to boot silently. 5. A search is made for further interfaces that may have firmware chips on them. This could include storage adapters and network cards. Further information about these cards may be displayed at this point and their memory addresses reserved. 6. The firmware may display a summary screen about the system configuration. This may scroll by quite quickly. Use the Pause key if you want to analyze it. 7. The operating system load sequence starts. Note: On modern computers, the POST happens very quickly to improve boot times so you are unlikely to see any POST messages. A modern POST is unlikely to perform thorough checks such as a memory count.
operation instructions on the cpu
1. The control unit fetches the next instruction in sequence from system memory to the pipeline 2. The control unit decodes each instruction in turn and either executes it itself or passes it to the Arithmetic Logic Unit (ALU) or Floating Point Unit (FPU) for execution 3. .The result of the executed instruction is written back to a register or to system memory. A register is a temporary storage area available to the different units within the CPU."
PCIe connectors.
A 6-pin (2x3) connector is used to supply an extra 75 W power (+12 V) to PCIe graphics cards. This was updated to an 8-pin (2x4) connector delivering 150 W in the ATX12V v2.2 specification. Some adapters or dual-card systems will require the use of multiple PCIe auxiliary power connectors.
intrusion detection
A computer chassis can be installed with sensors to report intrusion detection (if the chassis or lockable faceplate is opened) to management software or display an alert at boot time. Some setup programs can lock the workstation automatically if an intrusion is detected, requiring a supervisor to log on with the relevant password to unlock it again.
fun fact: The power output is not the same as the power the PSU draws from grid power. If a PSU works at around 75% efficiency, a 300 W supply would draw 400 W from the outlet. The extra energy is lost mainly as heat.
An ENERGY STAR compliant PSU must be 80% efficient at 20-100% of load (many vendors only display the efficiency obtained under low load). 80 PLUS is a similar rating scheme. The power adapters supply various combinations of 3.3 V, 5 V, and 12 V positive and negative current.
Multithreading
Another approach is Simultaneous Multithreading (SMT), called HyperThreading (HT) or HyperThreading Technology (HTT) by Intel.
critical update
As upgrading the firmware is relatively risky (a failed motherboard update can leave the computer unbootable, for instance), it is only worth doing if the update fixes a specific problem that you are encountering or if it is regarded as a critical update. Note: Performing a firmware update is often referred to as "flashing."
For many years, the system firmware for a PC was called the BIOS (Basic Input/Output System)
BIOS provides the industry standard program code that initializes the essential components of the PC and ensures that the design of each manufacturer's motherboard is PC compatible.
What is the typical wattage range for a cpu?
CPUs can range from 17 W to over 100 W, depending on the model)
Superpipelining
CPUs process multiple instructions at the same time (for example, while one instruction is fetched, another is being decoded, another is being executed, and another is being written back to memory). This is referred to as a superscalar architecture, as multiple execution units are required. Superscalar architectures also feature longer pipelines with multiple stages but shorter actions (micro-ops) at each stage, referred to as superpipelining.
If the PSU has a switch that enables you to change the input voltage, make sure that the switch is set to the input voltage you need.
Caution: Under no circumstances should you try to disassemble the PSU. It contains capacitors that can retain an electrical charge for hours after you disconnect the PSU.
whats an Entry-level Power Supply (EPS) specification?
EPS12V defines an 8-pin +12 V connector
Intel uses Land Grid Array (LGA) form factor CPUs
In LGA, the pins that connect the CPU and socket are located on the socket. This reduces the likelihood of damage to the CPU but increases the chance of damaging the motherboard.
p1 adapter
In the original ATX specification, the 20-pin P1 (2x10) adapter (also called the main connector) supplies power to the motherboard. Black wires are ground, yellow wires are +12 V, red wires are +5 V, and orange wires are +3.3 V. Most systems are now based on the ATX12V version 2 specification. This defines a 24-pin (2x12) P1 adapter to replace the 20-pin one. This is sometimes implemented as 20+4-pin P1 cable for compatibility with older ATX motherboards that have 20-pin adapters.
The address bus for most 32-bit CPUs is either 32- or 36-bits wide. A 32-bit address bus can access a 4 GB address space; 36-bit expands that to 64 GB. In theory, a 64-bit CPU could implement a 64-bit address space (16 Exabytes). In practice, the current generation of x64 CPUs are "restricted" to 48-bit address spaces (256 TB) to reduce the complexity in remaining compatible with 32-bit software.
Instructions are moved in and out of these registers to the system memory.
Integrated GPU
Most computer systems provide some sort of built-in graphics adapter. Initially, an integrated GPU would be implemented as part of the motherboard chipset
The system bus between the CPU and memory consists of a data bus and an address bus. The width of the data bus (64-bit on all current CPUs) determines how much data can be transferred per clock cycle; the width of the address bus determines how many memory locations the PC can access.
Note: In modern CPU designs, the bus is double or quad "pumped," meaning that there are two or four 64-bit transfers per clock cycle. Also, the memory architecture is likely to be multi-channel, meaning that there are two, three, or four 64-bit data paths operating simultaneously.
power problems
PC components need a constant, stable supply of power to run. If the computer will not start, it is likely to be due to a power problem. If the PC suddenly turns off or restarts, power problems are also likely. In the normal course of operations, the PSU converts the AC mains supply to DC voltages. DC voltage is used to power the internal drives and motherboard components. The PSU continually draws standby power from the mains (unless the PSU has its own on/off switch and it has been switched off). When the PC is switched on, the PSU starts supplying 12 V power and fans and disks should spin up. The PSU tests its 5 V and 3.3 V supplies, and when it is sure that it is providing a stable supply, it sends a "Power Good" signal to the processor. The processor then begins to run the Power On Self-Test (POST) program. POST will not run without a CPU. Some motherboards may be able to sound an alert or light a status LED if the CPU is not present or not working. If none of the LEDs on the front panel of the system case are lit up and you cannot hear the fans or hard drives spinning, the computer is not getting power. This is likely to be a fault in the PSU, incoming mains electricity supply, power cables/connectors, or fuses.
If power is present (for example, if you can hear the fans spinning) but the computer does not start or the screen is blank and there are no beeps from the speaker, it is likely that the
POST procedure is not executing. If the screen is blank, check that the monitor cable is connected and undamaged and that the monitor is powered on. If the monitor has separate inputs (for example, HDMI and DVI), make sure it is switched to the correct one. If possible, test with another monitor to confirm that there is no problem with the display. If you can rule out a problem with the display itself, other likely causes are faulty cabling or a damaged or mis-seated CPU or other motherboard component.
what is a rail?
Power distribution refers to how much power is supplied over each rail. A rail is a wire providing current at a particular voltage. The output of +3.3 V and +5 V has a combined limit. No combination of values actually adds up to 450 W For a modern computer, the output rating of the +12 V rail (or rails) is the most important factor, as +12 V is the most heavily used. A PSU with two +12 V rails can be referred to as dual rail. Each rail has a safety feature called Overcurrent Protection (OCP), which cuts the circuit if the current exceeds a safe limit.
Throttling
Power reduction/thermal control capability allowing CPUs to slow down during low activity or high heat build-up situations. Intel's version is known as Speed- Step, AMD's as PowerNow!. "In terms of CPU performance, more speed means greater power consumption and heat production. To deal with these issues, CPUs can implement power management to enter lower power states"
What is PSU?
Power supply unit that delivers Direct Current (DC) low voltage power to the PC components. The PSU contains transformers (to step down to lower voltages), rectifiers (to convert AC to DC), and filters and regulators (to ensure a "clean" output or steady voltage). The other important component in the PSU is the fan, which dissipates the heat generated.
CMOS setup, BIOS setup, or UEFI setup
System settings can be configured via the system firmware setup program. The term CMOS Setup is still widely used, even though the setup configuration is no longer stored within the CMOS RAM component.
Once the CPU has been given the power good signal, the system firmware performs the Power On Self Test (POST).
The POST is a built-in diagnostic program that checks the hardware to ensure the components required to boot the PC are present and functioning correctly.
One way to make instruction execution more efficient is to improve the way the pipeline works
The basic approach is to do the most amount of work possible in a single clock cycle (multitasking).
Serial Presence Detect (SPD) chip
The system software detects installed memory modules via a Serial Presence Detect (SPD) chip in the modules. The system software will allow you to enable or disable a boot-time memory check. There may also be options for configuring multi-channel memory modes. There may also be the option to overclock system memory modules.
Symmetric Multiprocessing (SMP)
The use of 2 or more physical cpu's in an attempt to make processing user instructions more faster.
boot sequence or boot device priority
This defines the sequence in which the system firmware searches devices for a boot manager.
The instruction set used by IBM PC compatible CPUs is called x86-32 or IA-32 (Intel Architecture)
Up until a few years ago, CPUs were designed to run 32-bit code. This means that each instruction can be up to 32-bits in length. A 32-bit CPU's General Purpose (GP) registers are also 32-bits wide.
Virtualization extensions
Virtualization software allows a single computer to run multiple operating systems or Virtual Machines (VM). referred to as hardware-assisted virtualization. This makes the VMs run much more quickly.
Resistance?
a degree of opposition to the current caused by characteristics of the conductor, measured in Ohms (Ω or R)
What are the characteristics of the electricity supply are measured?
as voltage, current (amperage), resistance, and power.
The maximum power output (power rating)
available from a PC power supply is measured in watts, calculated as voltage multiplied by current (V*I). The PSU found in a standard desktop PC is typically rated at around 200-300 W. Tower systems and servers often have units rated over 300 W. Gaming PCs might require 500 W.
multimeter
can be used to measure voltage, current, and resistance. Voltage readings can be used to determine whether, for example, a power supply unit is functioning correctly. Resistance readings can be used to determine whether a fuse or network cable is functioning correctly.
Trusted Platform Module (TPM)
chip on the computer motherboard. TPM is a specification for hardware-based storage of digital certificates, keys, hashed passwords, and other user and platform identification information." Essentially, it functions as an embedded smart card. Each TPM microprocessor is hard-coded with a unique, unchangeable key (the endorsement key). During the boot process, the TPM compares hashes of key system state data (system firmware, boot loader, and OS kernel) to ensure they have not been tampered with. The TPM chip has a secure storage area that a disk encryption program such as Windows BitLocker can write its keys to.
What is Direct Current (DC)
circuit, the charge flows in one direction from the positive to negative terminals of the power source at a constant voltage.
AMD uses Pin Grid Array (PGA) form factor chips
designed to fit in a Zero Insertion Force (ZIF) socket on the motherboard. As the name suggests, a PGA chip has a number of pins on the underside of the processor. These plug into corresponding holes in the socket. Care must be taken to orient the CPU correctly with the socket and to insert it so as not to bend or break any of the pins.
Power management
enables features such as soft power on/off (enabling the Windows Shut Down routine to power off the computer), power saving modes, hibernation, and so on. This option should normally be enabled
dual heat pipe
has two tubes, providing better cooling.
overclocking
increasing clock speed is done using the system setup firmware program by adjusting the CPU Speed or Advanced Chipset Features properties. You can either increase the core clock speed (multiplier) or the FSB speed (overclocking the memory chips) or both. Increasing the clock speed requires more power and generates more heat.
heat sink
is a block of copper or aluminum with fins on the side of the fan. A fan is an active cooling device. It requires power to run. A fan also needs to be matched to the CPU model to ensure that it is powerful enough to cope with the processor's thermal output.
Power Supply Tester
is a device designed (unsurprisingly) with the sole purpose of testing PSUs. Typical models come with ports for the 20/24-pin P1, Molex, SATA, plus 8-pin, 6-pin, and 4-pin connectors found on different models of PSU. Usually each pin on each port has an LED to indicate whether the voltage supplied is good or (in more advanced models) a reading of the voltage supplied.
Microprocessor
is a programmable integrated circuit (IC). An IC is a silicon chip embedded on a ceramic plate. A silicon chip is a wafer of purified silicon doped with a metal oxide (typically copper or aluminum). This doping process creates millions of transistors and signal pathways within an area called the die. These transistors provide the electrical on/off states that are the basis of binary computer systems. The process used to create the transistors is referred to as an n-micron or n-nanometer (nm) process, reflecting the size of the features (a transistor for instance) that can be created.
heat pipe
is a sealed tube containing some type of coolant (water or ethanol). The liquid close to the heat source evaporates then condenses at a cooler point in the pipe and flows back towards the heat source.
thread
is a stream of instructions generated by a software application. Most applications run a single process in a single thread; software that runs multiple parallel threads within a process is said to be multithreaded. SMT allows the threads to run through the CPU at the same time. It duplicates many of the registers of the CPU. This reduces the amount of "idle time" the CPU spends waiting for new instructions to process. To the OS, it seems as though there are two or more CPUs installed. The main drawback of SMT is that it works best with multithreaded software. As this software is more difficult to design, it tends to be restricted to programs designed to run on servers. Desktop applications software often cannot take full advantage.
Firmware
is specialized software stored in memory chips that store information whether or not power to the computer is on. It is most often written on an electronically reprogrammable chip so that it can be updated with a special program to fix any errors that might be discovered
What is electricity?
is the flow of electrons through a conductor.
The Front Side Bus (FSB) speed
is the interface between the CPU and system memory
The core clock speed
is the speed at which the CPU runs internal processes and accesses L1 and L2 cache (L2 cache access speed actually depends on the CPU architecture but full-speed access to L2 cache has been standard for some time)
if the computer is losing the correct time
it can be a sign that the Real Time Clock battery is failing. You may see a "CMOS Checksum" error or similar. To replace the CMOS battery: 1. Obtain a coin cell battery that is compatible with your motherboard. 2. Unclip the existing battery and take it out. 3. Plug in the new battery. 4. Switch the computer back on.
If POST detects a problem what does it generate?
it generates an error message. As the error may prevent the computer from displaying anything on the screen, the error is often indicated by a series of beeps.
cpu form factor
its a CPU packaging refers to how it is connected to the motherboard
Unified Extensible Firmware Interface (UEFI)
its another type of firmware for newer motherboards. UEFI provides support for 64-bit CPU operation at boot, a full GUI and mouse operation at boot, networking functionality at boot, and better boot security. A computer with UEFI may also support booting in a legacy BIOS mode
For hardware problems there may be:
light indicators LED flashes, alerts, overheating (could be unusual odors or burning smells could cause spontaneous reboots), loud noises (distinguish between "healthy" noises and "unhealthy" ones. For example, a hard disk may make a certain "whirring whine" when first spinning up and a "chattering" noise when data is being written, but clicking, squealing, loud noise, or continual noise can all indicate problems.), and visible damages to the computer.
Drive encryption
means that the entire contents of the drive (or volume), including system files and folders, are encrypted. Windows supports drive encryption in the BitLocker product, bundled with the Professional/Enterprise/Ultimate editions.
what are voltage regulators?
on the motherboard are used to correct the voltage supplied from the PSU to the voltage required by the component.
CPU (Central Processing Unit)
or simply the processor, executes program instruction code, performs mathematical and logical calculations, and controls Input/ Output (I/O) functions. The CPU is commonly described as the "brains" of a computer; in fact, it is better thought of as a very efficient sorting office.
System firmware
provides low-level code to allow the computer components to be initialized and load the main operating system software
Liquid-based cooling
refers to a system of pumping water around the chassis. Water is a much more effective coolant than air convection and a good pump can run more quietly than numerous fans. Liquid cooling is an active cooling technology as the pump requires power to run.
how to test the fuse
set the multimeter to measure resistance and touch the probes to each end of the fuse. A good fuse should have virtually zero Ohms of resistance; a blown fuse will have virtually infinite resistance.
Current?
the actual flow of electrons, measured in Amps (I). A current flows in a circuit, which is made when conductors form a continuous path between the positive and negative terminals of a power source. The size of the current is determined by the conductivity of the circuit (for example, a higher current can flow in a thicker wire than can in a thinner one).
Energy?
the amount of power consumed by a device over time. This is measured in Watt-hours (or more typically, Kilowatt-hours [kWh]).
Voltage?
the potential difference between two points (often likened to pressure in a water pipe) measured in Volts (V).
Power?
the rate at which electricity is drawn from the supply by the device using it, measured in Watts. Power is equal to the Voltage multiplied by the Current (W=V*I).
what to do If it seems that the PSU voltages are correct and that all power connectors are properly in place
then there may be a fault or overload on one of the peripheral devices (for example, the optical drive or the hard disk). Remove one peripheral device at a time (turn OFF when removing and reconnecting devices) to confirm whether the fault lies with one of these units. If you still cannot identify the fault, then the problem is likely to be a faulty motherboard or adapter card.
SecondLevel Address Translation (SLAT)
this is a second generation of virtual extension to support a feature of virtualization software designed to improve the management of virtual (paged) memory. These extensions are referred to as Extended Page Table (EPT) by Intel and Rapid Virtualization Indexing (RVI)by AMD"
Chip Level Multiprocessing (CMP)
this is another word for a dual-core cpu. A dual-core CPU is essentially two processors combined on the same die (which is an area where microprocessor integrated circuit process creates millions of transistors and signal pathways)
real time or real time clock (rtc)
this is simply the calendar date and time. The PC's Real Time Clock (RTC) can be automatically adjusted back or forward one hour as appropriate, within the time zone under Windows.
