LCD (Liquid Crystal Display) monitors have come down in price considerably since their first release, but they still cost a good deal more than an equivalent-sized Cathode Ray Tube (CRT) monitor, the TV screen-like monitor most of us know so well. As a rough approximation, you'll pay twice as much for a flat LCD screen as your will for a good quality CRT.
Whether the LCD is worth the extra money depends very much on your financial state and other conditions.
The biggest advantage of a flat screen monitor is compactness. They are only a couple of inches in width, so they take up much less valuable desk real estate than a CRT. That makes them an ideal choice for office desks and people who don't have much room.
LCD screens are easier on the eyes because they offer better contrast than CRTs. That's important if you're a Baby Boomer whose eyes aren't what they once were.
And for those of us who have to move monitors occasionally, I'll opt for a flat panel any time over the 60-pound-plus 19-inch CRT.
However, LCD have drawbacks besides price. For one thing, colors tend to appear more washed out on an LCD. The same things that make LCD's easier on the eyes make it hard for them to display vivid colors. They also lack the multiple color adjustments you find on a CRT.
By their nature, LCDs don't handle fast-moving objects as well as a CRT. If you're a gamer, you'll probably be disappointed at the speed and image quality you get from an LCD. A less expensive, higher quality CRT will save you enough money to buy that high-end video card.
Unlike a modern (multisync) CRT, an LCD has a fixed refresh rate. This means that the image tends to get blurry when you try to change the screen resolution.
Of course, CRTs have their own drawbacks. They are big, heavy, consume a lot of power, and produce a lot of heat. They are also more likely to cause eyestrain, both from the characteristics of the screen and from reflections and glare.
As LCD technology advances, we can expect CRTs to go the way of the floppy disk and dot matrix printer, niche items used only for special applications. For now, you have to balance the advantages of an LCD against getting a bigger CRT for the same price.
Thursday, October 9, 2008
LCDs vs. CRT: Battle of the Display Acronyms
What's RAID 10 And Why Should I Use It?
RAID is, of course, a Redundant Array of Independent (or Inexpensive) Disks. It is a method of storing information on multiple hard disks for greater protection and in some cases performance. Under the RAID umbrella are a number of different storage methods, called levels and numbered from 0 to 9, some of which are more useful than others.
Each level is a distinct method of organizing storage, but some of them can be combined which produces a two-digit RAID level, such as RAID 10, sometimes identified (and more appropriately so) as RAID 1+0. In general, each RAID level has its own advantages and disadvantages.
RAID 10, for example, is fast, it's crashproof and it eats disk space. If you need more protection for your storage, or faster storage performance, RAID 10 is a simple, relatively cheap fix.
To implement RAID 10 you need at least two physical hard drives; just using two partitions on the same hard drive is inadequate. You also need a disk controller that understands RAID.
RAID 10 works by striping and mirroring your data across at least two disks. Mirroring, or RAID 1, means writing your data to two or more disks at the same time. Even if one disk fails completely, the mirror preserves the information. Striping, or RAID 0, means breaking your data up into chunks and writing the chunks to different disks in succession. It improves performance because the computer can get data off more than one disk simultaneously. (For the purists out there: RAID 0 technically isn't a RAID level at all because it doesn't provide any redundancy to protect information. However, it is commonly referred to as a RAID level anyway.)
Before we go on, here's one important caveat about backup and RAID 1. Although data is written to two disks simultaneously, the data is not being backed up. Should your system, rather than the hard disk, suffer an error erroneous data could be sent to both disks at the same time, corrupting both drives simultaneously. You still must have a backup strategy in place, even if you use RAID 1. (For greater protection against data corruption, use a RAID level that includes a parity drive, but that's a different story.)
Put RAID 1 and RAID 0 together and you get RAID 10. RAID 10 is secure because mirroring duplicates all your data. It's fast because the data is striped across two or more disks, meaning chunks of data can be read and written to different disks simultaneously.
The drawback to RAID 10 is that it cuts your effective disk space in half. Since everything is mirrored (duplicated), two 60 GB disks give you a total system capacity of 60 GB. And remember, always use identical disks when creating a mirrored array. The disk geometry (number of heads, cylinders, etc.) is critical, and using disks that are different is discouraged in the strongest terms.
Given the cost of disks, storage space is much less of a problem than it was a few years ago. It's cheap enough to add additional disks to support your RAID 10 array and if the disk controller on your motherboard doesn't support RAID 10, you can get an add-in disk controller card for less than $50.
RAID 10 is also slightly more complex to set up than conventional storage, but it isn't particularly hard. The system or disk controller software includes install routines that will walk you through the process. It usually takes just a few minutes to install a RAID 10 array.
Monday, October 6, 2008
Find maintenance level on AIX
# instfix -i | grep AIX_ML
All filesets for 5.3.0.0_AIX_ML were found.
All filesets for 5300-01_AIX_ML were found.
All filesets for 5300-02_AIX_ML were found.
All filesets for 5300-03_AIX_ML were found.
All filesets for 5300-04_AIX_ML were found.
make bootable CD AIX
Have you ever needed a bootable CD/DVD image because the one you have is lost, broken, or simply out of date. The following procedure can be a great help. mkcd and/or mkdvd can be used to create bootable images. Generally, these commands are used to create a bootable mksysb image. But these commands can also be used to create a boot-only CD/DVD that you can use to boot a system and then get into maintaince mode using the information on the failed boot device - e.g. AIX in installed, but not booting. Or you have a tape that is not bootable, Etc..
On any AIX system at the SAME kernel level as the system you are wanting to (re)boot (e.g. 5300-05)
1. # cd /var/adm/ras
2. # ls ./bosinst.data ./image.data | backup -ivqf /tmp/fakemksysb
3a: # mkcd -m /tmp/fakemksysb -d /dev/cdX ## X is device number of cd/dvd writer
3b. # mkcd -m /tmp/fakemksysb -S ## will create a .iso formated file in a "default location" - it will not end in .iso Transfer this file to system with a cd/dvd burner and burn the CD
Note that towards the end of the process there will be some installp error messages. You can ignore these.
