WHAT IS LIKELY TO BE WRONG IF YOUR COMPUTER DISPLAYS THE WRONG TIME AND DATE?
I have several old computers and it never ceases to amaze me that the time and date seem to always be correct. Granted the time may eventually get off by a minute or so but never by a large amount. The date is always correct. One of the computers is an old eMachine 700 which originally had a Windows ME operating system but now runs with Linux. It sat unused for several years because the operating system had crashed and I no longer had the restore disk or a Windows ME disk to restore the system with. After contacting Microsoft and being unable to obtain help or a new disk, I finally in despair downloaded Linux. When I rebooted the system I was surprised the time and date in the lower right corner was still correct.
I had a laptop I used in my travels for some time. It had a program which would check the time with an internet clock somewhere which in turn was linked to the atomic clock. If my computer got off a little it would reset the clock. The date was never wrong, and normally the time would not be more than one minute off. I often wondered how it always knew the time. Here is the answer. Located somewhere inside your computer on the motherboard is a chip called the CMOS. This little device preforms not only the task of telling the computer how to boot but also the correct time. My old Commodore 128 had to be booted from a diskette we usually referred to as a floppy. Before you pushed the start button you would insert the floppy in the A drive, push the start button, and wait for the computer to boot. The entire program for starting the computer was on the floppy. In some ways this was good, because the CMOS settings never accidentally changed. They only changed if you intentionally changed them. I don’t remember having any operating system other than the DOS program although at some point I did have Windows 3.0.
This process has changed somewhat with newer computers. Now CMOS remembers how to boot your computer, it also remembers the time. The program is stored in CMOS RAM. This can be a little confusing if you know anything about “memory.” RAM is a term for random access memory. An important thing about RAM is when power is lost, RAM loses its memory. The more RAM you have on your computer, the faster and better it works. While you work with your computer, information is suspended in RAM. Enough RAM will include the operating system and the application you are working with, as well as what you are typing or doing. If the application had to go to the hard drive for everything needed it would perform much slower. Hard drives are cylindrical with groves and sectors with the cylinder spinning at about 7500 rpms. If everything was stored on that cylinder the programs would have to search the hard drive every time you typed something into your work. RAM goes straight to the source with very little time lost in the search. Partitions are put on the hard drive when the computer is built. The first sector is a very small sector and contains the boot sector which is also referred to as the Master Boot Record. The boot process got there because it was following directions given by the CMOS RAM. There is just enough information in the CMOS RAM to send the computer to an address on the hard drive containing the memory boot record (MBR).
If something happens to the CMOS RAM the computer will not boot because it does not have an address for the location of the boot process. The computer is lost and has no idea where to go or how to get there. This is when you hope you have all of your application CD’s and all of your data has been backed up. To boot your computer you will either use a boot disk or a restore system. The restore program can either be CD’s you received with your computer or it may be a restore system located on the hard drive. This is in another predefined sector on the hard drive. If you must use the restore system all applications and data will be wiped clean and your computer will be restored to the original configuration. Now we need to know what caused this to happen in the first place.
In many cases the problem could possibly be found in the CMOS RAM. Your computer may have been warning you of this impending danger for some time, and you just shrugged it off. If your computer begins losing the correct time or date it is warning you that something is wrong. Since all RAM is volatile the CMOS RAM is no different. When power is lost programs and information in RAM are also lost with everything in CMOS RAM. The RAM located in CMOS remains when you turn your computer off or even unplug it from the outlet because it relies on a CMOS battery to supply power. It amazes me how long those tiny little batteries last. If you open the case on your computer and look around you will probably see the CMOS battery. It looks like a coin and is like the battery you would find in a camera, a calculator, glucose monitor, or many other small electronic devices. When it begins to go bad things begin to happen to your computer such as losing the correct time and/or date when you turn the computer off then back on again. If you want to avoid losing the ability to boot your computer and it begins displaying these simple symptoms, replace the battery before you lose your data.
Kermit
