The Near Future (A Treasury Of Computer Knowledge And Links)

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Here we scan the metaphorical horizon to see what changes may reasonably be expected in the near to middle future in the state of the art of computers and computing (broken down by main computer elements); the thought is to give you some idea as to what hardware and software you may have or be about to get is likely to remain current, or at least useful, for some time.

The Main Divisions On This Page:
o Cases & Power Supplies
o Motherboards
o CPUs
o Memory
o SCSI Controllers & Devices
o Hard Drives
o Video Cards
o Sound Cards
o Modems
o CD-RW & DVD
o Removeable Media
o Monitors
o Input Devices
o Speakers



Cases & Power Supplies

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Motherboards

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CPU Chips

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Memory

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SCSI Controllers & Devices

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The future of hard-drive control, at least in the SCSI world, is RAID. "RAID" is an acronym for Redundant Array of Inexpensive Drives. RAID was originally developed as a technique for assuring the integrity of data stored on hard drives even in the event of a drive failure. In the simplest possible form of RAID, the data is written to two drives simultaneously; thus, if either fails, the other still has the data saved. The "inexpensive" comes in because now neither drive need necessarily be an expensive, ultra-reliable one.

If that were all there is to RAID, it would not be a hot topic. But the more advanced forms of RAID are much smarter. With three drives, for example, what a RAID drive controller does is take each chunk of data and--to over-simplify a bit--write one-third of that data to each drive, all at essentially the same time. But, because the controller tacks on just a little bit of extra data to each partial write, you end up with a situation in which if any one of the three drives fails, the controller can completely reconstruct its contents onto a new replacement just from what's on the other two drives.

And that still doesn't get to the heart of RAID. Remember that the controller is, for all practical purposes, writing--in that three-drive example--each one-third (plus a little) of the data virtually at the same time. If you think that through, you'll see that what that necessarily implies is that the data is being written nearly three times faster than if it were being written conventionally to a single drive.

Now you can see why "inexpensive" drives are a feature of RAID: not only is the data integrity preserved if a drive fails, but the effective drive-access time is nearly N times that of any one drive in the array (where N is the number of drives total). For example, with a five-drive RAID the effective access is five times the speed of any one drive. Thus, slow (read "cheap") drives can be used to greatly outperform any one expensive super-fast drive. And in today's marketplace, even pretty good drives sell for not much over half the cost of a really cutting-edge fast drive (compare a 7200-RPM Viking II with a 10000-RPM Cheetah for example). So the cost of a modest three-drive RAID is only somewhat greater than that of an ordinary single drive.

There are many more permutations of RAID, identified as "Levels," depending on just how the drives are configured. There is even a "Level 0" at which there is no actual data redundancy (so that a drive failure will mean data loss) implemented solely for the speed-multiplying benefits of scattering the data across multiple drives (that scattering is called "striping" the data).

Here are a couple of more detailed explanations of RAID that you can peruse at leisue.

==>MasStor, short & simple.
==> University of Mainz, a little more detailed.
or just do an Alta Vista search using "What is RAID?" as the query.

So why isn't RAID nearly universal on the desktop right now? (It is already nearly universal in business environments, where continuity of service or integrity of data are dominating considerations.) Because while in a RAID the drives can be, and are, relatively inexpensive, the needed RAID controller is not--yet. If you think about what a RAID controller is doing, you will perceive that it's a pretty complex process. There are two ways to perform that task: in software--meaning that a program running on your computer figures out how to divvy up the data and parcel the writes out to drives (and how to fetch and reassemble it on reads)--or in hardware, meaning that the drive controller has dedicated chips on it that in effect function as a superspecialized computer dealing only with RAID writes and reads. Software RAID, being a complex process, can heavily load your CPU, slowing down overall system speed; it is not used except where a low price and data integrity are very important and system speed is not (there are such applications). But hardware RAID controllers, right now, today, are very expensive relative to non-RAID SCSI drive controllers (RAID cannot be readily accomplished, if it can at all, except using SCSI drives).

That situation, however, is on the threshhold of changing. Ordinary controllers for the new generation of Ultra2 LVD SCSI drives are around $200 street price; but one can already buy a good hardware RAID controller for between $450 and $500. It is my belief that in the near to, at worst, middle term, hardware RAID controllers will drop significantly in price as the market expands.

The implications of that for anyone assembling a new system from scratch right now are several. First, one needs to plan ahead for RAID. That means buying not one big fast drive but two or three smaller, slower (but still decent) ones. Right now, "big" means around 9 GB capacity, while "small" means around half of that, 4.5 GB capacity. Using my favorite example, the Quantum Viking II versus the Seagate Cheetah, one can have two 4.5-GB Vikings for just about the same price as one 4.5-GB Cheetah, and three 4.5-GB Vikings for less than one 9-GB Cheetah. That's a no-brainer, isn't it? But, RAID controllers having not yet come down in price, we need to accept that until they do--my guess is six months to a year--we have to get by without the special benefits, speed and otherwise, of RAID.

Since we will not need the 80 MB/sec. speed of Ultra2 in a non-RAID situation (the fastest current drives put out about 14 MB/sec. continuous, and a SCSI bus speed about three times that, or about 40 MB/sec.--Ultra speeds--will handily accomodate data bursts), we can and should look for an Ultra SCSI 40 MB/sec. controller card for now. We still have the extra storage space, and the data speeds, even without the RAID boost, are pretty good by modern standards. All we need add is a LVD-to-SE adaptor so we can run our LVD drives off the SE controller.

Or, as an alternative, we could get an Ultra2 controller now and plan on later adding a RAID SCSI-to-SCSI card. A "PCI-to-SCSI RAID" card--what I was discussing above--is one that plugs into a card slot in your computer (a PCI-bus slot) and acts as a RAID hardware controller. A "SCSI-to-SCSI" card is one that works with an existing PCI-to-SCSI card, standing between that card and the multiple drives of the RAID setup; to the PCI-based card, the SCSI-to-SCSI card "looks like" one single very large SCSI drive. Since a SCSI-to-SCSI card doesn't have to be both a SCSI controller and a RAID controller, it would, in principle, be significantly cheaper than a card that is both (the PCI-to-SCSI RAID card). But in the real world, it looks as if SCSI-to-SCSI cards are very little less expensive than PCI-to-SCSI RAID cards, so this may not be a good route to follow.

Specific hardware suggestions are on the page My "Ideal Computer" of this site.



Hard Drives

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Video Cards

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Sound/Audio Cards

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Modems

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CD R-W & DVD

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Removable Storage Media

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Monitors

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Input Devices

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Speakers

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(Last updated: 27 July 1999.)

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