Re: Computer hang! unable to boot system up and you are required to identify both com
In a situation whereby a computer hangs! unable to boot system up and you are required to identify both the common and unusual faults likely to occur in a personal computer.
(1) In the first place, what causes a computer to hang?
(2) Secondly, what makes a personal computer to be unable to boot system up?
(3) Thirdly, what are some of the common faults which normally occur in a personal computer?
(4) Last but not the least, what are the unusual fault which are likely to occur in a personal computer?
Reply:
(1) a computer system will most commonly "hang" due to a memory conflict/memory mapping error whereby the physical memory location where part of a program is stored during operation (RAM) or some other information such as settings are being temporarily stored (also in RAM) are overwritten and therefore erased (strobed over) this can be due to two different items of software attempting to utilize the same memory address for the storage of processing parameters at the same time or the settings and data from one program being overwritten by another program.......when a certain condition in the programming is met, the first program will reference (jump to) the memory location (address) to load another part of the software or retrieve settings and will attempt to load the new(incorrect) data from that portion of system memory and this will cause a system error and a freeze up, in particular if this causes the main operating system (O/S) to crash or the other program in question locks up the graphics processing hardware of the computer system, which will in turn cause the operating system to hang...
(2) Missing or corrupted/damaged Batch/ Bootloader files that the computer needs in order to allocate memory and begin loading and running the main operating system (or firmware when dealing with other hardware such as cellphones or an Ipod etc) this is also referred to in some industries (such as games console programming) as a Bootstrap (and an error referred to as a broken Bootstrap)
(ii) apart from that the memory where the operating system is stored may be damaged or the initial software that forms part of the bootloader may be damaged/corrupted/deleted.
(iii) also the BIOS settings (Basic Input Output System) stored on the ROM (Read Only Memory) IC Chip on the Hardware (Main Board*) may be misconfigured and prevent the operating system from being loaded, for example due to a change of Hard Drive or even something as simple as leaving an SD (Secure Digital) Card from a camera or a memory stick in a slot on the PC/Laptop/Netbook/Tablet.....when the start up sequence is set in a certain way the machine will try to load a non existent Operating system from the external memory then go no further....
(iv) Hard Drive Damage that prevents the O/S from being loaded and also deprives the system of usable memory, this can be caused by dropping/impact on magnetic hard drives due to platter (disk) damage and by overheating or Static Electricity damage on SSD Hard Drives (Solid State Device- chip Based )
*The Main Board is Also referred to and commonly known as the Motherboard or Logic Board , when speaking to an Apple computer technician they will refer to it as the Logic Board
(v) Thermal issues, the processor may lock itself off or shutdown immediately due to protection circuitry operating when it begins to start up/ turn on.....this is due to something called BIST (Built In Self Test) where the processor will check it's internal temperature on start up, then hardware logic and built in software (Burned in-part of the hardware internals) will attempt to start the cooling fan (or cooling Peltier Element {also known as a peltier heat pump}) and if the Fan has failed/broken/been damaged or stuck in position by impact damage or dust the processor will shut off to prevent permanent damage caused by heat (also referred to as thermal runaway) you can repair this by checking the fan, clean it with an Air duster such as the Falcon Dust off (you can get them easily, Made in the USA....I have one here beside me right now in Scotland...another brand is Servisol...also very good, made in the UK....sold in computer stores in the USA) and check that the Fan is free to move.....if the fan has failed then they are easy to buy in computer stores and on Ebay for a few Dollars and change out with only one 3 pin or 4 pin connector... Thermal paste is a good idea as well, this is a paste that gets squirted on to the top of the processor then the heatsink and fan assembly get pushed down onto that and screwed/clipped down...it helps with thermal transfer and stops heat building up so that the fan does not have to work as hard/spin as fast.... 2 good brands are Servisol (made in the UK) and AKASA(Made in Japan) which are both available in the USA.
A lot of computer start up issues are solved by applying thermal paste, this is particularly where graphics processor chips have dried out their thermal paste and it needs renewing between the graphics chip and the graphics heatsink, which can cause the computer to shutdown as welll, quite often during gaming or watching a movie when the chip starts crunching graphics operations and begins to heat up a bit...
There are a lot of Xbox and Playstation consoles that can be easily brought back to working condition by replacing thermal paste on the graphics chip, this is where the Red and Yellow rings start showing up...
Cooling fans have 3 or 4 wires, one of which sends out a signal (a square wave/clock pulse) each time it rotates, this is to allow for fan speed control and also indicates if the fan has failed, if there is no signal the computer will shut down to prevent damage..
(3) Common Faults on a Personal computer are
(A) a Broken/Damaged Hard Drive preventing system Start up….the Data can be recovered by a Data Recovery company with the right equipment..
(B) A dead power supply (PSU)
( C) overheating due to a build up of Dust, particularly in City and Industrial/machine shop environments or in dusty buildings like Student Dorms etc…this dust builds up in the main fan and heatsink as well as on the Graphics Card/Chips and also on the RAM (Random Access Memory) Cards…
Also problems can occur where Malicious Software (a computer “virus”) has been loaded onto the machine (“infected”)
(4) An unusual fault would be something like installing the wrong software Driver for a Graphics card and this causing the display to fail, or spilling a drink on a laptop/Netbook and this causing problems with the thin easily replaceable Ribbon cables/connectors inside the computer, the keyboard may not work or an internal connection may short out..
