Thursday, September 13, 2007

Computer Repair - 1: Beep Codes

This is the first in a series of computer repair series, which might come in handy for some crippling problems. So go through it and let me know if it was of any use.

So, your computer won’t start? On top of it, it sends out a beep(s) that seems like an SOS from the Titanic and you are worried that there is a serious problem with your computer.
Agreed, there is definitely a problem, but what is it?

How do you say what is the trouble without contacting the service centre?

When you power on the PC, the BIOS runs a diagnostic test, known as Power-On Self Test (POST). (What the heck is BIOS? BIOS is the acronym for Basic Input/Output System. BIOS is the software that is responsible for loading the operating system e.g. windows, mac etc. The POST is run by the BIOS to ascertain that the hardware is functioning properly).
In case the BIOS encounters an error, and it is unable to access the video card to display the error, it will “beep” out the message.

Beep Codes are the pattern the BIOS follows in order to point out which specific hardware is causing the problem.
These patterns will differ, primarily because of two reasons:

• The type of BIOS (basically three – AMIBIOS, Award BIOS and Phoenix).
• Type of motherboard - Different motherboard manufacturers use slightly customized codes.

Following is a list of AMIBIOS beep codes:

1 Beep : Refresh failure
2 Beeps : Parity error
3 Beeps : Base 64K memory failure
4 Beeps : Timer not operational
5 Beeps : Processor error
6 Beeps : 8042 - gate A20 failure
7 Beeps : Processor exception interrupt error
8 Beeps : Display memory read/write failure
9 Beeps : ROM checksum error
10 Beeps : CMOS shutdown register read/write error
11 Beeps : Cache memory bad

Now, excepting the 8 beep code, almost all other errors are fatal.

So, you know the beep code stuff and you can most probably tell what’s the nature of the problem with your computer. But after that, what?

Lets say you have a memory error and that includes the 1-3 beeps. The possible reasons are that:

1. If it’s a newly updated system, the memory type might not be compatible.
2. The memory might not have been stuck in properly.
3. The memory might have just gone bad.

Out of the above cases, cross-check with your vendor if there is a compatibility issue between the memory and the motherboard.
Then check the slots to make sure that the memory has been put properly in place. Finally if nothing works, get a new memory stick!
There is still one more issue that we didn’t talk about and that is a problem with the motherboard, in which case, you would still get a problem showing that the memory is causing an error whereas the mother board would be the real culprit.

For a 4-beep error, ‘timer nor operational’, one possible reason is that the mother board might be grounded (which is not such a good idea). Just check for any metal parts that might be causing the grounding, else, check if the mother board has been tightened too much. In absence of both, you can refer to your vendor if there is a hardware problem with the motherboard.

A 5-beep error signifies a processor problem. Either there is problem with the processor or motherboard or, there is a compatibility issue between the motherboard and the processor (if it is an assembled one). For starters, you can remove the CPU (please don’t do it if you don’t know how to – refer to a technician!) and reinstall it. If that doesn’t work, check with a new CPU compatible with your motherboard. Finally, check the mother board if there is a problem.

For a 6-beep error, the probable reason might be your keyboard. Check if the system is working with another keyboard. If that doesn’t work, reinstall the keyboard controller chip and if the problem persists, replace it. Check if the system is working with another keyboard.

(For a 5, 7 or 10-beep error, refer to the 4-beep error.)

For an 8-beep error, most probably, the video card memory is at fault, or some other part on the video card. Else, an incompatibility between the video card and the motherboard could be a problem.

A 9-beep error is a signal that the BIOS chip is at fault, which is a pretty serious problem and the motherboard parts/whole motherboard needs to be replaced for that.

(The above analysis is just for the AMIBIOS. However, for the same problem, only the mode of indication is different for different BIOS.)
Visit for beep codes for all types of BIOS.

Friday, August 17, 2007

Computer Main Memory - Part I

We have discussed about the selection of computer main memory. We shall do a bit more information sharing on the main memory in this series. We start off with accquainting ourselves with the computer main memory terminologies:

What are SIMMs and DIMMs? The computer motherboard comes with a RAM form factor. Basically, the size and type of the slot available corresponds to the compatibility of the motherboard with the type of memory module.

computer memory

The Single-In-Line Memory Module (SIMM) has 72 pins (earlier version had 30 pins). Pins refer to the contact points on the slotted end of the module, which fit into the computer motherboard. It has a redundant set of pins on both sides of the module.

The Dual-In-Line memory module (168 pin) is the predominant main memory available in the market today, because of its higher data transfer capacity because of a 64-bit path rather than a 32-bit path as offered by the SIMM modules. The main difference is that while the SIMM pins have electrical contacts on both sides that are connected, the pins on a DIMM have isolated electrical contacts which provide higher data rate.

The predominant DIMMs available in the market today are the SDRAM and the DDR SDRAM (types of DRAM).

What is DRAM? Dynamic Random Access Memory. The word Dynamic denotes the fact that the RAM is able to store data only if accessed constantly by the refresh circuit.
SDR(Synchronous Data Rate) RAM has the ability to synchronize itself with the timing of the CPU. DDR(Double Data Rate) RAM on the other hand, has double the rate of SDR, for e.g. if the SDR has FSB of 100MHz or 133 MHz, the DDR will have 200MHz or 266MHz speed respectively.
One of the most popular questions about the SDR and DDR memory modules is that, “Can we use both at the same time?” – The answer is NO. We can use only one type at a time but not both.
Apart from that, we have the DDR2 memory wherein the memory modules run at faster speeds (400 – 1000MHz range), however, higher latency causes it to run at a lower speed than DDR. To have similar/higher performance than DDR, look for DDR2 800MHz or higher.

What is the FSB (Front Side Bus) speed that we have been talking about? It is the speed at which the microprocessor communicates with the main memory and it is a function of the motherboard. We shall talk about the classifications of memory and the implications of FSB in the subsequent part of this article.

Thursday, August 16, 2007

How to select a computer main memory

What is a computer memory? Contrary to the popular belief, the term computer memory includes not just the computer's main memory, so popularly known as the RAM but aslo includes other memory modules available in the microprocessor,motherboard, your video card and so on and even your hard disk, but it is more popular as the secondary memory.

Before we get to the business of selecting the RAM for your computer, lets get familiar about computer memory and the various types available.

So what is RAM anyway? RAM stands for Random Access Memory. Mark the Random - it means that the memory, unlike the other versions of electronic memory that we know of, like the tape or the hard disk, doesnt need to search for data sequentially. In other words, the time required to obtain any data remains the same regardless of its location.
The first and most important characteristic of RAM is that it is fast.
The second characteristic of the Random Access Memory(RAM) is that it is volatile. Which essentially means - no power, no memory.

Why do we need a computer main memory in the first place?
The microprocessor of your computer is slowed up by rate at which data is transferred to it. In the absence of a computer main memory, the data rate goes down even further, thus resulting in undermining the true potential of the processor.

How does the computer memory - main memory that is, differ from the other types of RAM available on the various chips? High speed RAM is found on various parts, like the microprocessor itself - e.g. L1 cache - What is that?
The microprocessor requires a high speed memory area wherein the instructions and data can be held – that’s the L1 cache (For the Intel Core 2 Duo E6700, the L1 cache is 128 KB). Apart from that, there is its more popular level, the L2 Cache – That holds the instructions that might be used shortly (For the aforementioned processor, it is 4 MB). Now, the same memory, if available on the motherboard is classified as the L3 cache.
So much for the various types of computer memory. And again, we haven’t touched on the memory available on the video cards/graphics adapters and the like.

(All that is fine, but what about the jargon, DDR, SDRAM, DDR2 and the like?) Lets cut the history and get ahead with SDRAM first. SDR SDRAM stands for Single Data Rate Synchronous Dynamic RAM.
“Synchronous” because it operates at the system bus speed.
DDR SDRAM – The DDR stands for “Double Data Rate”. Hence, it operates at double the speed of SDR SDRAM and hence doubles up as the most popular form of computer memory.
The higher version of DDR, the DDR2 has already dominated the memory market despite some competition from RDRAM (Direct Rambus) - which died down over time. Now of course, a DDR2 and its successors rule the computer main memory market.

Getting to the part of selecting the computer main memory –

1. What system are you using? As much as it sounds funny, RAM incompatibility with motherboard needs to be verified, especially if you plan to upgrade your system’s main memory.
2. What is your operating system? As the complexity of the OS increases, the RAM requirement goes along with it. Currently Windows Vista shows good performance with a 1 GB memory than with lower ones.
3. What programs do you intend to use? If you are the compulsive gamer type, or use high memory applications like simulations, graphics processing etc, you definitely need higher computer main memory. 2GB for most high profile simulations is the norm.
4. Pricing – Higher priced RAMs are priced higher than other main memory counterparts because of the stringent testing they go through, the density they possess and higher temperature capacity. Betting on the high priced memory modules is a pretty safe option.

As for the future of computer main memory, there is the Z-RAM with its high density and capacitor-less bit configuration, which should offer much more powerful options than the memory modules available today.

Wednesday, August 15, 2007

Computer Microprocessors - Intel vs AMD

Intel vs AMD

Anyone who has been remotely associated with a computer has heard of Intel, regardless of whether he knows even the basic facets of a microprocessor.
Now, geeks of course, will cry foul if we leave AMD(Advanced Micro Devices) out, but the fact remains that Intel is still light years ahead of AMD when we talk about publicity – globally that is.

By Jolly, isn’t Intel ahead of AMD?

Talking about computing, is a different story altogether. For a long time, AMD had been nibbling away at Intel’s empire, falling short of the big brother’s powerhouses.
That was until it launched the AMD Athlon64 microprocessors which had almost got Intel by the throat.

Intel had been the industry leader in micro-processors till then with its forte being the performance of its Pentium Series.
During those times, Intel embarked on the Netburst architecture as its future plan for the next ten years (in 2000). And AMD concentrated on building 64-bit architecture and dual core processing as its objective.

Pretty soon, Intel realized that the Netburst line was not going the right way and cut short the plan to three years. But, by then, AMD was already ahead and going on, with its plans for launching the Athlon64. and then the dual-core version (Opteron) of the same in April 2005.

Most industry experts would agree that the AMD Athlon64 was probably the best micro-processor at that time for desktop PCs, outrunning the Intel Pentium D processor across all platforms. And along with it, came the accusations of poor quality of processors from Intel and for building sub-standard stuff.

All that and much more changed with the arrival of the Intel Core 2 Duo. Code-named Conroe, independent analysts agreed that this processor was one of the finest pieces of silicon ever manufactured, going over close to 20% of performance hike over its AMD counterparts. Close on the heels of the dual-core processor, came the Quad-core line from Intel, bolstering its stand.

All said and done, one would say that if you are looking for the best chip for your computer, look no further than Intel (That is for now, of course).

If you think that the battle between Intel and AMD hinges purely on the performance of their micro-processors, then you are wrong. Both parties have a history of litigation against each other, about broken agreements, copyright infringement (by Intel over its MMX series) and AMD complaining of arm-twisting by Intel for stopping its entry into global markets.
However, AMD has already proved itself and made sure that Intel stays on its toes and delivers in the micro-processor market.

Monday, August 13, 2007

How to select a computer motherboard

What is a computer motherboard or a ‘mobo’ anyway? It is the primary circuit board of your computer. It effectively means that it is one of the most important part amongst all the other devices present in your computer. And combined with the CPU (Central processing unit), it is the costliest as well.

So, if you are planning to get a computer assembled and would like to choose each device, how does the motherboard part come into it? That’s because all other parts depend on the motherboard for operation and compatibility with the motherboard is a must for the sound operation of your computer.

Before we get to selecting a motherboard, let’s get to know it a bit. A computer motherboard broadly consists of the following parts:
1. Processor: This is the part where the computer does its calculations. It is generally hidden behind the heat sink and the cooling fan.

2. Main memory: This is added to the computer motherboard in the slots available (DDRAM slots in the picture).

3. Other Components:·
ATX (Advanced Technology Extended) connector or, rather, the power plug-in for the motherboard·
PCI Slots – These slots are available for adding various components to the motherboard, such as sound cards, Ethernet Card (for LAN), etc·
AGP(Advanced Graphics Port) – For video adapters·
BIOS (Basic Input and Output) – The part responsible for initializing the vital components of the computer when it is turned on – (CMOS battery responsible for the BIOS is shown in the figure.)

Now let’s get to the question of actually selecting a computer motherboard. What features do you want in it?

1. Which processor are you planning to use with it – Check with your vendor whether the motherboard is compatible with the type of processor you want to use with it.

2. FSB (Front Side Bus) or Bus Speed – Check the FSB of the computer. It is the speed at which your computer communicates with the processor as well as with the PCI and the hard drives, although at a slower pace. If the speed of your hard disk is higher than the bus speed, you run the risk of underutilizing your hard disk.

3. Type of chipset – Check the type of motherboard chipset as the motherboard is basically dependent on it for almost all operations.

4. Memory Support – Which type of memory you need – SDRAM, DDRAM or DDR2. Most of the modern motherboards come with a DDR compatibility as it is cheaper and faster.However, check for the number of slots provided, so that you can upgrade the memory later.

5. Does it have an AGP Slot? (Find the AGP in the picture show at the end.) - This is necessary if you plan to use a video card for enhanced graphics performance.

6. How many PCI slots does it have? More number of PCI slots means more flexibility to add components such as sound cards, Ethernet cards etc. Go for a motherboard which has at least three slots.

7. Does it have an inbuilt sound or graphics card? – That means lesser driver conflicts and hence, better performance at lower cost if you are not the game-crazy type.Remember that choosing the motherboard determines the possibilities of up-gradation later. So keep that in mind.

Friday, August 10, 2007

Computer Power Supply Unit (SMPS)

SMPS - Switch Mode Power Supply - is the technical term for what we generally know as the computer power supply unit. It is basically a box-like device used for the supply of power to your computer unit. So what does it do? In very simple terms, it converts the AC (Alternating Current) power supply from the general electrical sockets available at your home to DC (Direct Current), basically the type of current you get from a battery. The "Switch" term in the SMPS comes from the fact that the computer power supply unit converts AC to DC using switcher technology. We now use the ATX supply power units for the computers as the industry has settled on a standardized case and motherboard (ATX).

Typically, three voltages (12V, 3.3V and 5V) are supplied by the power supply unit.

If you are selecting a computer power supply unit, how do you go about doing that?

1. The first thing of course is to know what power requirements you are looking at. You can check the power requirements of the various devices of your computer and add them up, or you can just ask the vendor for the same. Once you have the total wattage, (that will be the unit of power), you can go for a slightly higher rated SMPS.
Now why you want to do that is because, at a later point of time, if you want to upgrade your computer, like a new DVD RAM drive, you may need a higher power supply.
One more thing to remember is to check the actual wattage against what the label on the power supply unit indicates.

2. It is always a good idea to go for a branded power supply unit. But that might not help if price is an important criteria.
The SMPS supplies power to all the components of the computer, like the motherboard (24/20 pins), hard drives and CD ROMS etc (IDE 4-pin), floppy drives (Floppy 4-pin), etc.
What happens is that, once the computer is powered on, there is a surge of current and as a result, it gets heated up. The fan, in such a condition is crucial, other wise, high temperatures might result. You should have at least one 80mm fan. It is even better if there are two fans instead of one.
(One such problem is the continuous restart of your computer as the temperature rise due to a faulty power supply causes the computer to shut down without giving any error message, and in some cases, not even the BIOS screen.)

If you have a branded SMPS, you can rest assured that there is not much chance of such an event occurring.

3. Number of connectors and the efficiency rating – These two factors are at par with the other factors while considering the computer power supply unit. The efficiency rating, is important as it is directly related to the heat output and subsequent temperature rise. Higher efficiency rating ensures that the SMPS causes a lesser rise in temperature.
The number of connectors is important as it determines how many devices you can use with your computer.

4. Lastly, the noise level – Apart from the CPU fan, the SMPS fan also determines the amount of noise generated – Except from a fine whirring sound, which is basically indistinguishable, you should not have any other sound coming from the SMPS.

Wednesday, August 8, 2007

Selecting a computer mouse

Selecting a computer mouse is worth a laugh, right? Wrong. For most of you who are not aware of RSI (Repetitive Stress Injury – caused due to repetitive movements involving a specific set of muscles and joints, e.g. – trigger finger, carpal tunnel syndrome etc.), this seemingly small little instrument can cause injuries that are pretty disabling.

Though the fact is that RSI depends more on the posture than on the computer mouse itself, we shall concentrate more on the mouse than on the posture in this article.

Coming back to the topic of selecting a computer mouse, we shall discuss a bit as we go along the criteria for selecting it.

Optical Mouse

Does it fit? - Amongst the various computer mice available, seek the one that best fits your palm. Of course, customization is not possible, but across the various companies and models, the size changes and that might make a difference.

What type do you need? -

a) If you are using the computer for general purposes, it is ok to buy the good old scroll mouse. This is the most common type of computer mouse that has a roller at the bottom and has two buttons and a scroll wheel on the top. It is the cheapest and most widely used.

Disadvantages? – The lint and the debris that get between the roller and the connectors do not let the connectors function properly. Moreover, the accuracy and response of this once mighty computer mouse is not at par with its counterparts today.

b) Suppose you are a graphics designer or a gamer and you do not get a response from your computer mouse that is good enough for you. Enter the optical mouse. It looks the same as a scroll mouse but underneath, there is no roller that slows up the response. Instead, optical mice use a red LED (Light Emitting Diode) that throws red light onto a surface, which bounces off and is captured by a CMOS (Complimentary Metal Oxide Semiconductor) sensor. Now, as you move the mouse, the variations in the image captured by the sensors cause the cursor on your screen to respond accordingly.

Why is it more accurate? – The image response works at close to a hundred times per second. Variations of the optical mice which use laser technology are also available in the market.

c) Want to operate the mouse at a distance? Have a problem with the wires connected to the mouse? That’s when you need a wireless mouse. Most wireless mice that are available in the market are pretty reliable and the best thing about them is the fact that they can be used even when there is no clear line between the PC and the mouse (which is not so in the case of an infrared mice). That is basically because they are radio-based (RF-Radio Frequency) devices and hence do not require any optical or physical connection with the computer.

Wireless Mouse

Issues? – The first of course is the fact that you will need to charge them up for operation. Secondly, the computer will need to have a receiver – an external device, a built in component or a special card that you can place in an expansion slot.

The Bluetooth computer mouse is a type of wireless computer mouse that uses Bluetooth technology to connect to a computer. Another is the RF mice that can operate from a distance of 33m.