Aleksandar's computer workshop

Let's see what Aleksandar was fixing today.
My findings, tips & tricks related to computers, internet, programming and other stuff I was working with.

Slow computer, High CPU utilization, the stuttering DVD drive or the lame hard disk?

Do you experience: 

  • Suddenly very slow computer
  • Constant high CPU utilization during file transfer
  • Lame hard disk performance
  • The stuttering DVD drive
  • Choppy DVD playback
  • Your drive is always in PIO mode and you can’t set it to UDMA mode

If you have one of these problems most probably your drive has switches from UDMA to PIO mode.

What does it mean?

DMA is an abbreviation for Direct Memory Access, an access method for external devices where the data transfer is not done by the central processor, but by a small special processor called DMA controller. It uses a procedure called cycle stealing, where the central processor memory access cycles are delayed for very short times to intersperse DMA controller memory access cycles. Some newer, faster DMA modes are called UDMA (Ultra DMA).

The alternative, slow and inefficient data transfer mode is called PIO, Programmed Input-Output, where the central processor transfers data byte for byte or word for word. This requires many processor commands for each data word and therefore causes a high and unwanted processor load.

Solution is here:
1) Download the file from here: http://winhlp.com/tools/resetdma.vbs

2) Despite any warnings click on the [Open] or [Execute] buttons as required to execute the file resetdma.vbs. If you fear to download the file, you can use the manual method instead (see link below). Or you could download, save, and inspect the program with an editor like the Windows Notepad. It is a script text file.

3) If the program found any ATA channel to reset, reboot your computer and test all drives.

4) If the problem is still not solved, set the offending channel to PIO manually, reboot your computer, set the channel back to DMA, and reboot again.

5) Please report your results here http://winhlp.com/node/97.

For more technical background or menual method visit this site:
http://winhlp.com/node/10

Difference between S1 (POS) and S3 (STR) standby mode in BIOS?

Computer can be in several power or standby states. It's handled by so called ACPI (Advanced Configuration and Power Interface) power management specification.
I will skip long storry and in short describe "most important" states:

S0 Working: the normal working state of the computer, the operating system and applications are running. The CPU(s) execute instructions. Within this state, it is possible for CPU(s) and devices like hard drives, DVD drives, etc. to be repeatedly put into and come back from low-energy states. Laptops, for example, routinely power down all currently unused devices when running on battery; some desktops also do this to reduce noise.

S1 (POS) Standby: All processor caches are flushed, and the CPU(s) stop executing instructions. Power to the CPU(s) and RAM is maintained; RAM is refreshed; devices that do not indicate they must remain on may be powered down. Some newer machines do not support S1; older machines are more likely to support S1 than S3. This state can operate when a card or peripheral does not recognize S3. The most power-hungry of sleep-modes. POS means Power On Standby.

S2 Standby: System appears off. The CPU has no power; RAM is refreshed; the system is in a lower power mode than S1. It is not commonly implemented.

S3 (STR) Standby: In this state, the CPU has no power, the power supply is in a reduced power mode, main memory (RAM) is still powered, although it is almost the only component that is. Since the state of the operating system and all applications, open documents, etc. lies all in main memory, the user can resume work exactly where they left off the main memory content when the computer comes back from S3 is the same as when it was put into S3. S3 has two advantages over S4; the computer is faster to resume than to reboot, secondly if any running applications (opened documents, etc) have private information in them, this will not be written to the disk. However, disk caches may be flushed to prevent data corruption in case the system doesn't wake up e.g. due to power failure. STR means Save To RAM. In modern operating systems it's called as: Standby in versions of Windows through Windows XP and in some varieties of Linux, Sleep in Windows Vista and Mac OS X.

S4 Hibernate: In this state, all content of main memory is saved to non-volatile memory such as a hard drive, preserving the state of the operating system, all applications, open documents etc. That means that after coming back from S4, the user can resume work where it was left off in much the same way as with S3. The difference between S4 and S3, apart from the added time of moving the main memory content to disk and back, is that a power loss of a computer in S3 makes it lose all data in main memory, including all unsaved documents, while a computer in S4 is unaffected. A system that's in S4 can also be Mechanicaly Off (no power at all) and still keep its S4 save state information, so that it can resume the operating state after getting back power. This mode is also referred to as Save To Disk, Suspend to Disk, Hibernation in Windows, Safe Sleep in Mac OS X.

S5  Soft Off: The hardware is completely off, the operating system has shut down; nothing has been saved. Requires a complete reboot to return to the Working state.

How to fix Vista Multi Booting, HDD Cloning, drive letter and other boot problems

Today I had to migrate data from one HDD to another. Afected computer have XP and Vista in dual boot configuration.
In normal situation if booted with XP you will see only C: drive while Vista partition is hidden.
When booted with Vista second partiotion is visible as C: and first (XP) partition is D:
HDD was cloned using Acronis True Image 11 Home Edition. Due to fact that HDD was bigger than older one partitions size changed as well.
Everything worked perfectly until old HDDD was taken out and cloned HDD was used to boot from.

First boot XP was working perfectly. Visible is only C: drive and second hidden partition.
But after booting Vista I got some strange errors caused by drive letter change. Vista partition is now D:!

In order to fix the problem I have used "Drive Letter Problems" section from this page: 
http://www.multibooters.co.uk/cloning.html

After few registry entry changes, PC is restarted and everything works!!! GREAT!

I would higly recommend the article for following issues:

Dual/Multi Booting With Vista
Cloning Vista
Possible partition issues
Preparing the BCD
Curing drive letter allocation problems
Fix the BCD while working from another OS or the Vista DVD
Hibernation issues
Backup the BCD
Whole drive cloning

 

LCD Monitor test

Got new LCD? Well, go to this site and test how does it work and good it is (or not)
http://www.lagom.nl/lcd-test/

Quote from site:
It is hard to select a good LCD screen based on the specifications such as
viewing angle and contrast, since different manufacturers have different
opinions on how to measure these. I made these test patterns in order to check
out a few monitors in the shops before I purchased one. You can check the images
on this webpage or put them on a usb stick and try them in the computer store
like I did. If you are already stuck with your monitor, you can use this page to
adjust its contrast and brightness settings, or to show off how good (or bad)
your monitor is compared to those of your friends. With these test images are
much more revealing regarding monitor shortcomings than ordinary photographs and you can judge the monitor quality by eye.