matt@frisbee.UUCP (Matt Taylor) (05/13/88)
[ Sorry to cross post this, but I wanted to generate some thought on this subject. I've yet to hear some good discussion on where optical technology fits and where it doesn't. ] In article <13212@brl-adm.ARPA>, PAAAAAR%CALSTATE.BITNET@cunyvm.cuny.edu writes: > The logical place for optical disk technology is to use > it in place of Magnetic tapes > (1) for distribution. > A CD-ROM is smaller, lighter, offline printable, > stores a vast amount of data, > and is very hard for the Postal Services to erase or damage. > > (2)Write-Once-Read-Mostly Optical technology is an excelent replacement for > archival magnetic tape - about the speed I believe but better > volume and much harder to erase or accidently overwrite. I even think > that someone has a plug compatable Mag Tape replacement > > Dick Botting (doc-dick) Those are two very good, astute observations. The standard misconceptions are present however. One of the more difficult things the general public has yet to discern is the real, applicable difference between CD-ROM and WORM (Write-Once-Read-Many. Yes, it used to be Read-Mostly but not any more). Barring the obvious technological differences, the CD-ROM has the advantage of cheap, mass replication of data. The WORM has the advantage in flexibility and portability. What??? portability you ask? Yes. True portability implies the capability to exist and function through OS or hardware changes. "The data usefully outlives the machine that produced it". For example, that means taking your database originally created under DOS (cringe), and "transparently" mounting it on something like a Sun, Mac, VAX, etc. Both types of media have a distinct and separate position in the market place. One needs to restrain from taking a new technology and forcing it where it doesn't belong. "Gee! Lets put our monthly financial records on CD-ROM" or "Hey! Lets put our annual financial statement on a WORM and make 10,000 copies for our shareholders". Wrong. It may seem obvious in the extreme examples above, but it sometimes gets very confused by the consumer and the manufacturer. On the other hand, experimentation with the technology in the market place is vital and needs to continue. What does all of this have to do with the above quote? (Finally!). Well, there seems to be some misconceptions between magnetic tape and WORM. The new 5 1/4" WORM products are extremely efficient and fast. The typical benchmarks show data reads being 92-97% of a 28ms hard disk. Writes are somewhat slower (the verify pass slows you down) and come in around 62-78%. Combine that with the WORM's high density along with an efficient, transparent OS interface and you have a really good, useful product. The key word here is useful. If it's not useful, nobody (okay, typically nobody) will use the damn thing. (Something to be aware of, disk space efficiency is one of THE major components and usually the hidden gotcha!). Now we have a technology we can all use. By looking at both WORM and CD-ROM technologies and using them where they fit and avoiding using them where they don't, you can achieve the maximum benefit of both. Standard disclaimer: I have nothing to do with WORMs except design and write file systems for them and use them in my garden. -- Matt Taylor @ Maximum Storage, Inc. Colorado Springs, CO. 303-531-6888 {cbosgd,handel,hao,hplabs}!hp-lsd!frisbee!matt