History of the Computer - Cache Memory Part 1 of 2

We looked at the early digital computer memory, see History of the computer - Core Memory, and mentioned that the present standard RAM (Random Access Memory) is chip memory. This conforms with the commonly quoted application of Moore's Law (Gordon Moore was one of the founders of Intel). It states that component density on integrated circuits, which can be paraphrased as performance per unit cost, doubles every 18 months. Early core memory had cycle times in microseconds, today we are talking in nanoseconds.

You may be familiar with the term cache, as applied to PCs. It is one of the performance features mentioned when talking about the latest CPU, or Hard Disk. You can have L1 or L2 cache on the processor, and disk cache of various sizes. Some programs have cache too, also known as buffer, for example, when writing data to a CD burner. Early CD burner programs had 'overruns'. The end result of these was a good supply of coasters!

Mainframe systems have used cache for many years. The concept became popular in the 1970s as a way of speeding up memory access time. This was the time when core memory was being phased out and being replaced with integrated circuits, or chips. Although the chips were much more efficient in terms of physical space, they had other problems of reliability and heat generation. Chips of a certain design were faster, hotter and more expensive than chips of another design, which were cheaper, but slower. Speed has always been one of the most important factors in computer sales, and design engineers have always been on the lookout for ways to improve performance.

The concept of cache memory is based on the fact that a computer is inherently a sequential processing machine. Of course one of the big advantages of the computer program is that it can 'branch' or 'jump' out of sequence - subject of another article in this series. However, there are still enough times when one instruction follows another to make a buffer or cache a useful addition to the computer.

The basic idea of cache is to predict what data is required from memory to be processed in the CPU. Consider a program, which is made up of a series instructions, each one being stored in a location in memory, say from address 100 upwards. The instruction at location 100 is read out of memory and executed by the CPU, then the next instruction is read from location 101 and executed, then 102, 103 etc.

If the memory in question is core memory, it will take maybe 1 microsecond to read an instruction. If the processor takes, say 100 nanoseconds to execute the instruction, it then has to wait 900 nanoseconds for the next instruction (1 microsecond = 1000 nanoseconds). The effective repeat speed of the CPU is 1 microsecond.. (Times and speeds quoted are typical, but do not refer to any specific hardware, merely give an illustration of the principles involved).

In part 2 we consider what happens when we introduce a cache memory.

History of the Computer - Cache Memory Part 1 of 2

Laptop Memory

History of the Computer - Cache Memory Part 1 of 2

History of the Computer - Cache Memory Part 1 of 2
History of the Computer - Cache Memory Part 1 of 2

Laptop Memory

Memory Dump - Computer Memory Problem

Computer may have many types of memory problem as it is one of the most important factors in the functioning of the computer. All the data necessary for the operation of the computer is stored in the memory slots. It is always difficult to detect a memory problem if there is no error message displayed by windows. A memory problem can be caused due a physical problem with the computer or sometimes due to improper maintenance and not clearing the old files leading to a stage where windows starts memory dump.

A problem with the memory of the computer can make it crash and give some serious errors and blue screens. Sometimes the system fails to recognize the installed memory. Severe memory problems can be found quickly as the BIOS checks the system memory before booting the computer. If there is a serious error; the computer will just have a blank screen and an unbootable computer. The problems could lie on the memory but there is a higher chance that your registry is the main cause of the memory dump. If there is a corrupted data, there is a high chance that you memory stop responding which causes a blue screen to appear that says beginning of physical memory dump. This can cause the computer memory module to fail. Some effects of this are missing or scrambled data, system crashing very frequently and sometimes reboots all on its own. Registry files and system files could be lost because of this which makes the windows to dump the memory of the RAM to a file. Memory dump is useful as it stores the data and details about the crash and can be useful in analyzing what made the system to crash.

There is hardly anything which can be done if there is a computer memory problem other than changing the physical part which is damaged and try to fix it with registry cleaner.

So things which can be done to prevent computer memory problems are buying memory devices of good quality, not mixing the memory modules of different manufacturers, keeping the computer in good environment which is free from dust, humidity and extreme heat which can damage the computer's physical components. Keep the computer safe from power fluctuations by providing power backup. Spending little time for maintenance of the computer can do a lot of good which will include performance and trouble free computer.

Registry cleaner is a much better option because it is free to download. You can scan for free to see if the actual problems lie on your system registry. You will need to purchase it to fix the problems, which is a better choice since memory is more expensive than the software. The other advantage is that you can maintain your registry to prevent the memory problem to occur in the future.

I bet you are thinking that the second option is more sensible and smart move. If you do not want to see a blue screen of death or a message that says beginning of physical memory dump, check out computer memory problem for further information.

Memory Dump - Computer Memory Problem

Laptop Memory

Memory Dump - Computer Memory Problem

Memory Dump - Computer Memory Problem
Memory Dump - Computer Memory Problem

Laptop Memory

Troubleshooting Computer Freeze (Lockup) Problems

How familiar does the following sound? Your computer was working fine, but then suddenly started locking up (aka hanging or freezing), rebooting itself (crashing) or shutting down spontaneously? If you know only too well what I am talking about, then read on! Performing the simple steps below can fix the majority of lockup cases.

1. Check for recently installed software or hardware.

If the lockups started to happen after you installed a new peace of hardware, new software program, or new drivers, uninstall it and see if the problem goes away.

2. Run your antivirus program.

One of the first things to do in the case of sudden lockups is to run your antivirus program. Check your antivirus manufacturer's website for updates and latest virus definition files. (This is absolutely necessary, outdated antivirus is not going to be of any use!) If you don't have antivirus software installed - or if updates are unavailable - run one of the web-based antivirus scans that some major antivirus vendors like Trend Micro are offering for free. You can find a comprehensive list of available web-based scans and free antivirus programs on http://www.free-antivirus.info.

3. Run some good spyware removal tool.

If your machine is not infected with any viruses, it is still possible that it has some harmful adware or spyware is present. Download and run some good spyware removal tool such as AdAware or Microsoft AntiSpyware. Check http://www.free-antivirus.info for a list of free spyware removal applications.

4. Check for free hard drive space.

When no viruses are found, check out free hard drive space on drive C:. Make sure there is more than 20% of free space available; low disk space can lead to random lockups.

5. Check for overheating.

Overheating is another known cause of lockups. It can be caused by problems with fans inside the case, dust buildup, or other cooling problems. Make sure the power supply fan and CPU fan are running and free of dust buildup. You can check the temperatures inside the case by running Motherboard monitor
http://mbm.livewiredev.com
- make sure the temperatures are within the preset limits. Be very careful while cleaning inside the computer case (use plastic vacuum crevice tool) and NEVER OPEN THE POWER SUPPLY CASE as it contains high voltage.

6. Check the hard disk.

Check the hard disk - it is possible that its logical structure is corrupted. To check the disk for errors, right-click on the disk C: icon in "My Computer", select the "Tools" tab, check all check boxes in the "Check disk options" field, and press the "Check now" button. It should ask whether you want to schedule the check next time you restart your computer - answer "Yes" and restart your PC. The check will be performed automatically after startup; it can take a while, so be patient. The program will attempt to fix some problems automatically - however, if the hard disk is failing physically, it will need to be replaced. It is also a good idea to run Disk Defragmenter (located in Start Menu > Programs > Accessories > System Tools) to optimize data placement on the hard disk for increased performance and reliability.

7. Check the memory.

Sometimes random lockups can be attributed to the computer memory (RAM) starting to fail. You can test the memory by running Windows Memory Diagnostic that can be downloaded from http://oca.microsoft.com/en/windiag.asp. If memory problems are found, try re-seating the RAM (pull it out and plug it back in). If it doesn't work, replace the defective RAM.

8. Check for other hardware problems (advanced users).

More hardware-related problems can be diagnosed by running hardware tests from the Ultimate Boot CD that can be downloaded from http://www.ultimatebootcd.com. However, you should only use it if you know what are you doing - some programs on that CD can be dangerous when used inappropriately (for example, some of them can wipe the contents of your hard disk).

9. Update Windows and drivers.

Some lockups can be caused by outdated software components - update your windows and drives by running a windows update: http://windowsupdate.microsoft.com (it's good idea to run it regularly).

The above steps will help diagnose and eliminate the most common causes of lockups. Hundreds more of other possible scenarios need to be dealt with on a case-by-case basis, as it all goes down to your particular computer configuration. Asking on PC
troubleshooting forums/newsgroups should help you figure out solutions to not-so-obvious lockup cases.

Troubleshooting Computer Freeze (Lockup) Problems

Laptop Memory

Troubleshooting Computer Freeze (Lockup) Problems

Troubleshooting Computer Freeze (Lockup) Problems
Troubleshooting Computer Freeze (Lockup) Problems

Laptop Memory