In this day and age, many are those who keep large amounts of digital media on their hard drives. Movies, episodes of their favourite TV series, anime, porn movies; usually not quite legal, as they - especially when it comes to movies - are often in violation of copyright, brought to digital form through DVD ripping or some other DMCA-violating method. Having this media on your computer is not currently illegal, or rather, people found to be in possession of such files are not currently prosecuted, and neither are most people who distribute them. If we look at software piracy (aka warez), the situation is different, but digital media pirates - the most common form of which are those who download and share music - are currently pretty much free to go about their business; after Napster became a victim of the law some time ago, several new services have arrived to take its place, many offering a far greater amount of media, many allowing the traders complete anonymity.
However, as it stands today, the hard drives which ship with most personal computers are far too small to handle large amounts of digital media, which tends to be quite expansive. While thousands of MP3 music files will fit in just a few Gbytes, full-length movies often occupy as much as 600-800 Megabytes each, and an entire TV series can take several Gbytes of data storage space all by itself. Recent digital VCD rip releases of new Star Trek series Enterprise take as much as 400 Mbytes per episode, putting the grand total for one season at a staggering 10.4 Gbytes. Bear in mind that it wasn't too long ago that just one Gbyte was considered an awesome amount of data.
Now, with high-quality movies and videos taking up increasingly large amounts of disk space, the user is forced to take action in order to fit it all in; either delete old stuff to make room for new, or expand the disk space he already has, or find alternate storage for his media. The first option is seemingly the most practical, but can easily lead to trouble as most computers today only ship with 40 - 80 Gbytes of hard disk space, and older computers have even less. 40 - 80 Gbytes may seem like a lot, but once the operating system and other pieces of software necessary to use the computer for anything but watching videos on is in place, as little as 10 Gbytes may be left, meaning very little digital media will be able to exist concurrently on the drive. Also, one often wishes to watch great movies of the past again, causing problems if they've been deleted (doh!).
The second option may feel close at hand for many - "Hey, my hard drive is out of space; I need a new one!" easy to do, but while hard drives have gotten cheaper, they're still not quite cheap - and there's a limit on how many you can put inside one computer. Most computers sold today have two IDE buses - two devices on each make for a maximum of four devices, and at least one will be spent on a CD/DVD drive. Some computers have four buses, allowing eight devices, but then the amount of physical space inside the computer's chassis may become the limiting factor, instead. This won't stop the hardcore hard drive collector, though; a cheapo SCSI card will allow 15 or more extra hard drives, which can be placed in an external case if required. Sure, there are limits of the amount of drive letters available (at least under Windows), but using RAID, several disks can be made to function as one. Given a large amount of money, it's not hard to set up 1 Tbyte (1,024 Gbytes) of hard drive space this way.
The third option, finding alternate storage, is often quite easy; if a CD burner wasn't included in your system when you bought it, one can be acquired for a relatively small of money (approx. $100 and up) and once installed, it can burn a seemingly endless amount of discs for you. Sure, there are other options - such as recordable DVD's - but they're still much too expensive. I'm also going to leave out MiniDiscs, Zip, Jaz, CompactFlash, bog standard floppies .. they have the same basic advantages and disadvantages as CD-R discs, with differing amounts of storage space and media reliability - not to mention different cost. I will let CD-R represent the third option, being the most common type of portable, recordable, storage today.
Having assessed our options, we now know of two good and proper ways to find storage space for all your digital media. Either you install a bigger hard drive in your box, or you get a CD burner and start pushing out CD-R's. Both methods have advantages and drawbacks when compared to each other. Let's look at prices, first.
HD: 5400rpm ATA100 40gb ...... $77 .... $0.0018/Mb
HD: 7200rpm ATA100 40gb ...... $96 .... $0.0023/Mb
HD: 7200rpm ATA100 75gb ...... $235 ... $0.0030/Mb
HD: 10Krpm U2WSCSI 36.4gb .... $1805 .. $0.0484/Mb
CDR: 12x 1x650mb ............. $0.6 ... $0.0009/Mb
CDR: 16x 50x650mb ............ $0.75 .. $0.0011/Mb
CDR: 12x 100x700mb ........... $0.40 .. $0.0006/Mb
CDR: 24x 100x700mb ........... $0.30 .. $0.0004/Mb
As should now be obvious, CD-R's are way, way cheaper than hard drives, and prices depend more on how many you buy at once than on the quality of the discs. Brand-name CD-R's from Kodak or Sony are generally more expensive, but they rarely offer a real performance advantage. However, if you're looking for cheap but (judging by hard drive standards) slow disk space, you can get fairly close to CD-R pricing with a 5400rpm drive. Note that I didn't include SCSI cards, RAID adapters, CD burners or other items not part of the actual media in the prices. This was mainly to simplify things.
Now, we get to the physical properties of the discs and drives. Hard drives may be somewhat heavy, but once inside your chassis, you won't notice them much unless you regularly carry your computer around, as some of us do (see: LAN party) on occasion. CD's, on the other hand, have a tendency to disappear or assemble in unsturdy towers of jewelcases, sometimes resulting in the downfall of said towers, causing mass CD-R scratching and much swearing from the owner of the discs. Not good. Also, each disc requires a jewelcase, an easily broken piece of thin plastic which offers little protection and makes it a more complex operation to retrieve each disk, while the main advantage of the hard drive remains that its contents are easily and instantly accessible so long as the computer is operational. However, while most good CD-R's will last a 100 years if kept free from unnecessary dust and scratches, hard drives contain moving parts which have a limited lifespan, so called MTBF or Mean Time Between Failure. Also, cheaper HD's can fail without warning due to poor design or low-quality parts. CD-R's, once successfully written to, won't suddenly break down, nor do they have any moving parts, and even a somewhat scratchy CD can usually be read by a CD drive of high quality - meaning its contents, while now slightly corrupted, can be moved to another disc. However, all CD's should ideally be stored in a manner which keeps them away from dust and scratches, such as a CD Wallet or storage case. CaseLogic (
www.caselogic.com) sell both kinds of storage, and I have personally had great use for their model CDW 208 nylon CD wallet as storage for my discs. Hence, the argument that CD's are bulky to carry around and store, is invalidated.
At this point, the following should be noted: 208 CD-R's at 700 Mbytes each, for a total of 145.6 Gbytes of storage, together with one nylon CD wallet holding 208 discs and one 12x CD burner, brings the price per megabyte to a staggering $0.0014/Mb. Still cheaper than a cheap hard drive, and with the added bonus that you can easily carry the discs around, let friends borrow them, make copies of them or vice versa. CD-R's do, however, have another disadvantage when compared to hard drives: reading/writing speed. On CD drives and burners, speed is measured in the peculiar unit x, where 1x = 150 Kb/s, 2x = 300 Kb/s, and so forth. Most new CD drives today read at speeds in the area of 36x, 48x or even higher; modern CD burners operate at 12x, 16x or 24x. While higher-performing drives are, of course, always on their way, these speeds are quite sufficient for playing digital media directly off a CD-R disc: a high-quality DVD rip in DivX format might have a bitrate around 150 Kb/sec, leaving a huge margin of expansion up to the 6 000 Kb/sec (40x) and beyond, which most readers are capable of.
Let's recap ... Hard drives: Expensive, can't have too many of them in same chassis, offer instant access to content, moving parts increase risk of failure, very high read/write speeds, usually not portable. CD-R: Very cheap, you can have thousands of them if you like, accessing content may take some time if no reliable system to determine what's on which disc exists (such as a Microsoft Excel document), relatively slow but undoubtably sufficient read/write speeds, highly portable, easy to copy. That about sums it up, I think. Thank your for reading. Please msg me with any comments or corrections.