MICRO CENTER: COMPUTERS AND ELECTRONICS
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In The Lab
From The Mail Bag - SD Cards, Hard Drives, Servers, Sleep Mode & DDR
by chris

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Q: What exactly is the basic use of an SD flash card. (What is the SD)?

A: There are numerous uses for flash memory cards. The most common is as storage media for digital cameras. At the same time, more desktop and notebook computers are coming with one or more flash card readers as standard equipment while floppy drives are becoming less common. SD stands for Secure Digital and is just one type of flash media card. There are currently three physical sizes for SD cards, including standard, mini and micro sizes. Many of these cards ship with adapters that allow you to use a microSD card in a slot designed for the standard SD or miniSD cards. The same holds true for using miniSD cards in a standard SD slot. Many of the other card styles like xD, Memory Stick, etc. are also adapting smaller formats.

SD Cards
A comparison of SD card, mini SD card and micro SD card sizes

Standard SD cards have a tiny write-protect slide switch on the side. This allows the user to make the contents of the flash card read-only (to protect against accidental erasure). SD Cards have internal circuitry to control access to copyrighted material depending on the type of device it is used in and can restrict transfer or unauthorized duplication of music, video or other data. SD cards are generally limited to a maximum of 2GB of storage, for capacities of 4GB and higher, SDHC (High Capacity) versions are available. Just like high-capacity diskettes, SDHC devices and readers should read non-HD SD cards just fine, but the reverse is not true. Devices designed for SD media may not be able to access SDHC cards. (Check out the SD Card Association site for more information)

With a reader installed, flash cards can be used just like any other storage media to backup important data or just to move file between systems. In cameras, they are used to store your digital photos or movies. In phones or PDA devices, they can store programs, music, video, Ebooks, or any other type of data file you can think of. The obvious advantage of using flash memory in these card styles is that the memory is non-volatile (the card does not require continuous power to maintain the contents of the memory).

Q: I bought a laptop with a 120GB hard disk drive. Is there a need for a 300GB USB hard drive?

A: This is a tough question, only because you don't indicate what you use your computer for. The point of any external drive is to provide additional storage over and above what is installed in the computer. In the case of an external USB drive, you gain some additional advantages over, say a network storage device, whether it is a file server, or a Network Attached Storage (NAS) drive enclosure.

Like any storage device, you can use the USB drive to move very large files between computers. If one of the systems has a TV tuner card, you could capture TV or movies to the drive and take them along to view later. Text documents don't tend to be very large, but pictures, music, and video files can quickly use up a 120GB drive without even trying. You can archive older files to the drive so you still have access to them, but they do not take up space on your notebook. Most importantly, you can use the external drive to maintain a backup of your entire 120GB disk, even if your built-in hard drive is getting full. If anything were to happen to the 120GB drive, you would have your backup to be able to restore files to a new hard drive, or access copies if the notebook is not available for some reason.

Q: I have acquired a Dell 6400 server system. It has the server software on it and I wish to use it as a super workstation, but cannot load a regular Windows Pro OS. It won't see the boot IDE drive as it has a SCSI 8 HD drive system that apparently overrides the CMOS boot routine... or I don't know what. How do I get this system to look like a normal windows workstation with a SCSI 8 drive subsystem?

A: The problem sounds like Windows is not detecting the SCSI controller, and for that reason, it won't see any drive or drives attached to it.  You really only have a couple of choices here. One would be to install a drive type that Windows XP can detect, such as an IDE drive or SATA drive (if your system supports it). If you have no free IDE or SATA connections, a workaround may be to install a drive controller in an available expansion slot. If you have a free drive connection, you should be able to install Windows to that drive. Once at the desktop, you still may not be able to see the SCSI drives until you have a driver, unless it can be detected and use one of Windows' standard "boxed" drivers. If no driver exists for the SCSI controller, then this approach becomes you only real option. If you can find XP drivers for the controller, then try the next approach instead.

When booting Windows XP to install the OS, one of the questions you see before it starts copying files (you have to be able to specify the target drive before you can copy files), is a message to press F6 to install drivers. To use this step, you must have the appropriate Windows drivers available on a floppy disk (XP won't support swapping CD drives or support pointing to flash drives at this stage). You need to watch for the message to add drivers (it occurs fairly early in the blue-screen text-based setup process), Press F6, then follow the instructions to insert the driver diskette, and select the SCSI controller. If all of that goes well, then the setup program should see your SCSI drives and allow you to select one as the target.

One other thing; if there is more than one drive attached to the SCSI controller and these are configured as a RAID cluster, you may also see some sort of POST message from the SCSI controller to press a control-key or Function-key to enter its BIOS setup. You will still need the diskette-based drivers, but the BIOS setup may control how the disks are configured, including making, breaking, or configuring the RAID configuration.

Q: When I bed down my HP computer it won’t stay in SLEEP MODE. When I leave the room to go to bed myself it wakes back up. After a while of this I'll have to shut it down. Any suggestions?

A:  There are usually only a couple of things that would "wake up" a computer as opposed to not entering a "Sleep Mode" in the first place. One reason for the computer coming out of sleep mode is that it is responding to some activity that fits one of the criteria for exiting a low power condition. These functions have been around just about as long as the power save feature and include activity specific to your specific system. The first and most obvious is a wake on "key" or wake on "mouse" activity. Some computers require you to press the power button to "wake up" the computer, others support "wake up" if the mouse is moved or any key on the keyboard is pressed. If you are using a wireless mouse or keyboard, I suppose it might be possible that there is some sort of wireless interference that is being interpreted as one of these actions. However, I would also expect that you would be seeing other interference issues such as random characters or jerky mouse movement if this were the case.

Two other types of input that are designed to wake the computer are a request from the network or modem activity. Features that are implemented in Windows and other operating systems are: Wake on LAN or Wake on Ring. If this was a modem issue and you share the phone line with a modem, I would think you would notice the computer waking up only when the phone rings. On the other hand, network activity is not so obvious, especially if you have a cable modem, DSL, or another always-on connection. You can check your device properties, either in device manager or from Control Panel > Network Connections > Adapter > Properties settings. There may be some setting under an "Advanced" tab that could control the type of activity to wake the system, or a "Power Management" tab where this option ties into your sleep mode settings. On my adapter there is a checkbox to enable or disable the Wake on LAN feature. Make sure yours is turned off.

Wake on LAN Settings
Ethernet adapter Wake up Type properties
Wake on LAN Settings
Ethernet adapter Power Management properties

The first portion of this answer addressed those things that are supposed to wake up the computer. Unfortunately, it is more likely that you have something that is not behaving as it should or is a symptom of a different problem. If your computer does not enter standby mode, it could be as simple as the system board chipset drivers need to be reinstalled. It can also be that you have some program or device driver installed that is preventing the computer from entering standby in the first place. If this was working, and stopped staying or entering standby recently, try to identify what changed or what you installed since the problem started. Drivers are difficult to troubleshoot blindly, so it helps if you can narrow down a time frame when this started or what was recently changed or added. You can try to first enter device manager and "disable" possible devices to see if that has any effect, or uninstall or rollback drivers as an alternative.

Before doing the next step (a bunch of trial and error testing), make sure your anti-virus definitions and Windows updates are current. Run a complete system scan with Windows Defender, anti-virus, and if you have it, anti-spyware or anti-adware tools. If you did not notice the problem starting after a change to the system that you made, then it might just be caused by one you did not notice happening. Anti-spyware and anti-adware could easily be running in the background and causing these symptoms.

You can attempt to troubleshoot programs and services that are interfering (or waking the computer back up) by using the Microsoft Configuration Tool (MSCONFIG). From the Start Menu, click Run..., enter "MSCONFIG"  in the box (without quotes) and click OK to run the application. You should see a "Services" tab and a "Startup" tab along the top. Services run in the background, but may also be responsible for causing the computer to exit from standby. Turning these on and off can cause other problems in the system, so use some caution and try to identify what you are disabling by the service or manufacturer names. I definitely recommend using the option to "Hide all Microsoft Services" since these include your critical Windows files. Pretty much anything else may be disabled to find out if it is the cause of the wake-up problem (lots of trial and error here). The same goes for the Startup tab. These are program files that are executed when Windows starts up. You can always disconnect your computer from the network, disable all startup items and see if the computer still wakes up. If not, then you have already started to narrow down the cause of the problem. If you turn off something you did not mean to, just replace the check to enable it again.

MSCONFIG Services
Windows MSCONFIG Services
MSCONFIG Startup
Windows MSCONFIG Startup

Q: I have to replace the memory and hard drive in an HP Pavilion A1000. It originally came with DDR. What is the difference between DDR and DDR2? Can an older system handle DDR2?

A: DDR stands for Double Data Rate, it is a type of SDRAM (Synchronous Dynamic Random Access Memory) that can perform a transfer twice for each cycle of your computer's clock. Standard (non-DDR) SDRAM can only perform a single operation during each cycle. DDR uses the leading edge and the trailing edge of the clock's pulse for timing, allowing double the performance. DDR2 doubles it again, meaning it handles as many as four times the number of transfers as standard SDRAM.

Not only are the electrical characteristics different between SDRAM, DDR and DDR2, but the "package" design is different as well. DDR memory has 184 pins along the bottom connector; DDR2 and DDR3 have 240. To prevent installing the wrong memory in a computer, a "notch and key" are used to align the module in the memory slot and to prevent installation of incompatible modules or inserting the memory backwards in the slot. Here's a comparison of the different modules; and while the notch positions may look close, they are off just enough to make it unlikely you would get these modules installed into the wrong slots.

DDR RAM Comparison

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