Possible errors in the computer

In the first chapter, we are going to talk about the messages displayed when the computer boots. But what if the computer won't turn on at all?

First of all, you need to check if power is being supplied to the computer. Maybe you forgot to turn on the surge protector (popularly called "pilot", Fig. 1.1) or an uninterruptible power supply? If the filter is on, then check the power connector itself - it so happens that you touched the computer, which violated the "fit" of the cable.

Some processors pay for the luxury of having a different register for each branch that fits in the target buffer: they are said to perform local prediction. Others prefer to use one register for all connections: they make a global prediction. These branch prediction modules contain one history register that is used for all connections.

The advantage of these prediction boxes is that any correlations between branches are taken into account, but this fails: if two branches converge into a branch prediction box with the same historical data, it will change the same counter to saturation.

Rice. 1.1.

Network filter

If everything is ok with the power and cable, look at the back of the computer. There is often a small switch on the power supply. Make sure it is in position 1, not 0, that is, on.

In fig. 1.2 shows a computer power supply (usually it is mounted in system unit). There is an on / off button above the power connector (Fig. 1.3). It should be noted that not every power supply has such a button.

Obviously, it is absolutely imperative to find a solution. Use these prediction blocks to limit as much as possible the cases where two different branches with the same history use the same saturation counter. To do this, we will perform a small operation between the history and some bits of the address of these branches to find which counter to use.

And the problem arises because of this: two different branches executing at different times can change the same counter to saturation: it is enough for the connections preceding these branches to position the history register with the same value. then the branch will be predicted not according to its history, but also according to the execution of branches that are independent and that have changed the same counter, and this interference tends to lead to bad predictions that should have been avoided.

Rice. 1.2.

Power Supply

Rice. 1.3.

The connector to which the power button is connected (the plug is usually signed by POWER SW)

Therefore, we need to find a way to limit the case. To do this, four researchers decided to come up with a new decision branch prediction system: the goodness predictor. This consistent predictor will allow you to remember for each individual branch if this one is most often taken or not taken, storing this information in a special bit called the offset bit. Thus, our consensus predictor is divided into two schemes: a two-level adaptive predictor, and also a scheme that will calculate the offset bit.

This bit offset is computed using the saturation counter associated with the branch target buffer. Each branch will be identified by its address in the target branch buffer, and each branch will have a saturation counter for that branch alone, which will know if our connection is frequently used or not.

Rice. 1.4.

Computer case

So, everything is fine with food. This means that you need to open the case (Fig. 1.4) to find out the reason. If your computer is under warranty and a warranty for the entire system unit, that is, it is sealed, then, of course, you do not need to open it, but you need to take the computer to service center- let them figure it out for themselves, otherwise you will lose the guarantee.

The solution will take into account the two branch prediction schemes, checking that the two branches agree. When the two branches disagree, it is possible that there was interference. Such branch predictors are even able to predict exactly which branch will exit the loop by treating it as taken!

It's very simple: their branching box contains a circuit that specializes in predicting connections of this type of loops. Each time the branch is executed, the value contained in the counter is incremented. For the first time, loopback connections are predicted using static prediction or congestion counters or any other branch prediction method. Example. In the next chapter, we will introduce the basic features of the product and test basic computer testing.

You can open the system unit if:

The warranty has already expired;

The warranty is given for components, that is, the numbers of components are written on the warranty sheet, and the system unit itself is not sealed.

The question is, what will we see if we open the case? We must measure the voltage of the motherboard battery (Fig. 1.5). It should be 3 V.

The emergence of the GUI is in line with today's trends, so don't expect anything revolutionary. The capabilities of the program are divided into 4 main groups.

System scan - checks your computer and fixes errors.
Using the resource of the system consultant.

The System Scan tab is the main building block for most common operations. Here we have the following checks.

Fragmented Disks Disk Errors History Track Junk Files Registry Errors. For each section, there are several areas that you can check the settings for the user. The meaning of the individual options is clear and the manufacturer has used standard terminology here, which is also known to the less experienced user.

Rice. 1.5.

Battery on system board

If the battery runs out, you will not be able to turn on the computer. You can measure the voltage with a voltmeter. Don't you have it? You don't need to buy it - buy another battery, it costs much less than a voltmeter (one dollar versus four).

For the average user, we recommend that you always provide the highest branch of the tree - then everything under the trees is automatically marked and checked. We recommend using regular tests only to check for register errors, unnecessary files and track history.

This is caused by the Scan Now button, which you can click and select the scanning method you want. Scan and Repair Only Scan, Repair and Scan, Repair and Shutdown. The choice is clear, we will not describe them in detail.

You can buy a battery at any computer store... You need a CR2032 (3V) battery. It's inexpensive, so replacing it won't ruin you. How long the battery will last is hard to say. She did not live on one of my computers even two years after buying a computer. And on my very first computer, bought in 1997, the battery is still alive. Believe it or not.

If you want some results in the results, select Scan Only. If you want to know more about bugs, just click on the selected group in the list and the details will appear in the window. Go back to the list of errors, then click the Back button. When it comes to error detection, it's time to fix the problem and fix the errors.

Return to the main screen of the program by clicking the "Back" button. These are quick tasks that can be done automatically. Clear Browsing History - Clears the browsing history of the Internet browsers that users use. Memory optimization - loss and defragmentation of computer memory. ... As soon as you click on one of the quick tasks, nothing happens - only on the bottom toolbar you will find information about the current task and its status.

Replacing the battery is very simple: gently use a screwdriver to squeeze the retaining clip and remove the battery.

Was it the battery? Well, that's nice! But it so happened that she did not last long? Then the matter is either in the battery itself (the purchased battery turned out to be expired - next time pay attention to the expiration date), or in motherboard... If the next battery also quickly fizzles out, then the reason is most likely in the motherboard. Then decide for yourself which is better: either change the motherboard, or change the batteries every month.

It’s much worse if the computer still doesn’t turn on after replacing the battery. Take a look at the motherboard. Sometimes it has a power indicator (usually red). If the indicator is on, and the computer does not show any signs of life, then you will have to change either the processor or / and the motherboard.

If the indicator is off or not at all, you need to determine if the power supply is working. Pay attention to the fan: if the fan does not work, then you need to change the power supply.

If you can't find a suitable power supply, you can prepare to replace the chassis. I do not recommend repairing the power supply - try to find a power supply that can be installed in your case, or immediately buy a new case.

Text error messages

Each computer has a basic input / output system (BIOS, Basic Input / Output System). One of the BIOS functions is the Power On Self Test (POST) function.

POST is a computer self-test program. Runs immediately when you turn on the power of the computer and tests the video card, processor, memory, disk controller, keyboard and other important components of the computer.

Table 1.1 lists the most common POST text messages. Since the BIOS can be from different manufacturers, the error messages may differ slightly, but still text message you can understand the essence of the error, but it will be the same regardless of the BIOS version and manufacturer.

Table 1.1.

POST text messages

Rice. 1.6.

Memory modules

You don't see any diagnostic messages at all

In some cases, instead of diagnostic messages, the logo of the manufacturer of the motherboard (or computer) is displayed. To see the POST diagnostic messages, you need to go into the SETUP program (usually the Del key is used for this, which must be pressed one to two seconds after turning on the computer power), enter the Advanced BIOS Features menu and turn off the Full Screen Logo Display option (the name can be slightly different, but the essence should be the same: display a full-screen logo). Then you need to save the settings (F10 key) and restart the computer (usually this happens automatically after saving the settings).

On the internet, I found an article on what to do if, when the computer starts, it writes an error message.

So, after turning on the computer, the POST program for self-testing of computer devices starts. After its successful completion, the BIOS searches for the device from which the computer will boot. This device can be any data carrier - HDD, USB flash drive, CD / DVD drive, etc.

How is this search done?

The fact is that the BIOS already has a list of devices from which it is possible to boot the computer and the search for a boot device is carried out in accordance with the order of devices in this list. The BIOS section that contains the list of boot devices is usually called Boot, and the order of devices in this list can be changed if desired.

While loading computer BIOS scans all devices from the list in order until it finds a device with boot files. At this, the search for boot devices stops and control of the computer's boot is transferred to the program, boot files which were found (in most cases, this program is the Windows operating system).

Order of devices in the list BIOS boot can be changed. This is usually done as follows: immediately after turning on the computer (at the stage of passing the POST check), you need to press the Delete key.

In this note, I publish photos of the screen of the ASUS EEE PC 1000H netbook, the BIOS view in your case may be slightly different

Sometimes the BIOS access key may be different and this needs to be clarified in the manual for the motherboard, but in most cases it will be Delete or, in my case, F2.

Once in the BIOS, you need to find the section responsible for the boot sequence from the devices. This section is usually called Boot.

To navigate the BIOS menus, the cursor keys are typically up, down, right, and left arrows. To enter a section of the menu, use the Enter key, and to exit - Esc.

In the Boot menu, you will see the following list:

So, after passing the POST check, the BIOS polls all devices in the list in order until it finds an available boot device. The presence of a device in the download list does not mean that it is physically present on the computer. So, in the boot list, the CD / DVD drive may be in the first place, but at the time of loading, the disk will not be inserted into the drive and therefore the BIOS will go to the next device in the list.

Once the boot device is found, the computer boot process continues from it. A special active section of the device is detected, in which the boot information (files) is located and the kernel is loaded operating system, to which then all control of the computer boot process is transferred.

If such a device is not found, or there are no boot files on it, or the boot files are damaged, an error message is displayed and the boot process stops.

There may be several errors:

Non system disk

Invalid system disk

System disk error

NTLDR is missing

What if you see one of these messages?

First of all, find out in the BIOS the order of booting from the computer devices. It is possible that you have a CD / DVD drive first and a disc was inserted into it during boot.

If the message continues to appear, then most likely damage has occurred. system files... There can be a lot of reasons for this - from infecting a computer with viruses, to unreasonable actions of the user himself. In this case, you can try to restore Windows, but this is a very delicate matter and it is very difficult to recommend here a clear algorithm of actions that would suit everyone and in all cases.

If the crash is caused by viruses or malware, you can try to restore the system performance using Dr.Web LiveCD or Dr.Web LiveUSB. it free programs with which you can boot your computer not with hard disk, but, from a flash drive or CD. Then you can scan your computer for viruses and fix problems.

There are hundreds more programs that help recover your computer after a crash, but they are all built on the same principle as the ones mentioned above.

And one more tip - if on the computer, or rather on the C drive (system drive), you did not have anything of great importance, then the most simple solution problems will be reinstalling Windows

If there is important information, then the matter becomes more complicated. I would recommend not to try to restore the operating system, but to remove the hard drive from the computer, connect it with a second drive to the working computer and move the necessary information from drive C to another, for example, D. Then return the hard drive back and reinstall the operating system with the formatting of drive C ...

Why don't I like to restore Windows? Because, as my experience shows, this is a thankless and temporary business. As a rule, such errors occur in very "cluttered" operating systems and the restoration of several damaged files does not globally solve the problem - soon either the problem repeats or new errors appear. Therefore, I prefer, firstly, to keep my operating system clean, and secondly, I never bother with recovering damaged files, but reinstalling the system from scratch.

Of course, reinstalling the operating system for a novice user is a dark affair and it is unlikely to do without outside help, but it is still worth learning.