Definitions Part 01
Section 01 -- All them Funky Terms
CD, DVD, DL, RW, etc
- CD is an abbreviation for compact disc which we are all familiar with. Available (common and uncommon) are 184MB, 220MB, 650MB, 700MB, 800MB, 830MB and 900MB with the most widely available size being 700MB. CDs with a capacity less than 650MB are often calledMiniCDs
- DVDs are widely recognized but often mis-abbreviated: DVD is an abbreviation fordigital versatile disc andnot digital video disc (because if it was, DVD Video wouldnt quite make sense). DVD capacities are given as a per-layer value as DVD technology allows for multiple layers to be present on a disc. The most common size is 4.36GB although commercial DVD fabs have access to 7.95GB discs
- DVD5, DVD9 Since DVDs can vary drastically in size, we use DVD5 to denote discs with a 4.36GB capacity and DVD9 to denote those with a 7.95GB capacity. Why the disparity? Because marketing people insist on messing up Giga- as being 1000MB and as such DVD5s are often marketed (incorrectly) as having 4.7GB capacity and DVD9s having 8.5GB.
- DL, an abbreviation fordual-layer. this is in reference to the fact that DVDs allow for multiple layers on a given disc. As the name would suggest, dual-layer discs have two such layers and thus doubling their capacity
- RW, an abbreviation forre-writeable and it means just that -- a disc with a RW suffix can be erased and rewritten on again and again. Yes there is a limit to the number of times you can re-use a disc but by the time you get anywhere near that limit odds are you'll have damaged the disc due to accidental scratches or what-not already
- R,-R,+R. With CDs, the R suffix was an indication that the discs could be written on (i.e., to discriminate between CD-R and CDROM). When DVDs came along, the industry was fractured into two factions, +R and -R each with their own proponents and their benifits/flaws. Again, both DVD+R and DVD-R discs can be written on (so long as the burner supports that disc type) however it should be noted that for DVDs there is no "plain R" i.e., DVDR.
- BL is an abbreviation for BluRay Disc which is a next generation optical disc format with capacities of 25GB per-layer. In comparison to current DVD discs which max out at 7.95GB/layer, all the extra capacity is possible by using a much shorter wavelength laser to read/write which in turn, allows for tighter packing of data and a greater overall capacity. BluRay competes with HDDVD
- HD-DVD is an abbrviation for Hi-Density Digital Versitile Disc (not high-definition!!). HDDVD discs can store 15GB per-layer which is less than their competitor, BD but HD-DVD discs are cheaper to produce as they are direct descendents of standard DVDs
MultiSpeed, HighSpeed, UltraSpeed, UltraSpeed+
These terms define speed grades for CD-RW discs and burners,
- Multispeed discs are rated 4X to 8X (it is important to note that not all 4X discs are classified as Multispeed however thankfully as we no longer have to deal with these discs, the nuance is no longer an issue)
- HighSpeed discs are rated 10X to 12X
- UltraSpeed discs are rated at 16X and 24X
- UltraSpeed+ discs are rated to 32X
It should be noted that very often, laptop optical drives (and
especially true for older laptops) will have issues reading HighSpeed (or better) discs, Most modern drives should be able to handle UltraSpeed and (to a lesser degree), UltraSpeed+ discs.
CLV, CAV, PCAV, ZCLV
These are acronyms for the various different approaches to "burning CDs/DVDs faster". Short of being an optical drive engineer or something, this is not going to affect virtuallly anyone and is included for thoroughness sake
- CLV This one is straight forward: constant linear velocity: here there is a constant number of sectors passing under the sensor per second and as such it is really easy to, with good accuracy, determine how long it will take to burn a disc. Due to the physics of rotational motion, the drive is constantly changing its velocity so that the same number of sectors passes under the read/write heads per second. For the most part, pure CLV is limited to about 12X for CD burning
- CAV. An alternative to CLV is CAV (constant angular velocity) and this approach is based on the principle of keeping the spindle speed constant. The downsides to this approach are that (a) it's not easy to calculate the time it takes to burn a disc because the burn speeds is not the same for any given moment (i.e., the burn speed accelerates) and (b) in theory, if we burned a disc using 12X CAV and a disc using 12X CLV, the CLV-burnt one would finish sooner -- and while there arent any modern overlapping scenarios like that, back in the day, this was possible. The upside for CAV is that you can have a significantly improved maximum speed. Burning CDs as speeds in excess of 12X or DVD+R media is based on this principle.
- Z-CLV. An improvement over the clunkiness of CLV, Z-CLV or Zone-CLV divides a CD/DVD into sets of concentric rings and while the sensor is within each ring, it maintains a given CLV speed (i.e., think of it as the optical drive "gearing up" as it moves from the inside to the outside of the disc). Many modern drives (including those for DVD-R burning) are based on this model
- P-CAV, Short for Partial CAV, this model is the marriage of both core models: while the burner is processing the earlier parts of a disc (near the center of the disc), the drives uses a CLV model and after a certain point, the drive switches into CAV mode so that it can accelerate through the rest of the burning process.
ATIP
Absolute time in pre-groove, this is. for all intents and purposes, the signiture or thumbprint of a optical disc. This information tells the burner and/or burning application everything it needs to know about that disc and is absolutely critical when discussing optical media. Here is an example of an ATIP dump (given by Alcohol120):
By using the ATIP information, we can refer to a disc in an extremely exact manner rather than saying "Oh those Maxell/Sony/Verbatim/TDK/etc discs I bought were really good". (it should be noted that neither Maxell, Sony, Verbatim nor TDK make discs at all).
C1/C2, P0/P1 Errors
Burning media is not a perfected process which is immune to error; with CD media, quality of media/burner/process is judged by the number of C1/C2 errors present and with DVD media, P0/P1 errors. C1/P0 errors are generally very basic errors and are automatically corrected on the fly by the drive (and for all intents and purposes, cannot be affected by the end user). C2/P1 errors on the otherhand are directly influenced by factors like burn speed and media quality (needless to say, burning faster generates more C2/P1 errors).
CD/DVD Images?
It is possible to store an exact image of a CD or DVD onto a harddrive for archival purposes, performance purposes or even for distribution. There are numerous formats available to perofmr this function each with their own benifits and drawbacks
- ISO As the name suggests, this is the de-facto, cross platform standard format for storing CD/DVD images however at the same time, it's universal compatability and ease of use limits its capabilities (no error correction capacity and no ability to store any subchannel data). An inadvertent benifit this is that, since they cannot store any extra information, they tend to result in the smallest filesizes. The defnining technical characteristic of ISO files is that they are Mode1/2048 essentially meaning they are Mode 1 images (not horribly important) and that they hold 2048 bytes per sector.
- BIN/CUE Originally developed on the Mac platform but now fairly common, the image of stored across two files, the BIN (which holds the data, i.e., the important stuff) and the CUE (which holds interpretation information, i.e., not important). The advanatage that BIN/CUE have over ISO is that they can hold error correction information as well as additional information required to make proper images of copy-protected media (albeit very old/weak protection schemes only). BIN/CUE files are split into two categories: Mode1/2352 and Mode2/2352: both store 2352 bytes/sector howevever Mode1 is usually reserved for Data images and Mode2 for media images)
- IMG/SUB/CCD, MDF/MDS, BWT/BWA These are image formats designed specifically to be able to store subchannel, data density and other information required to make proper 1:1 copies of protected media. IMG/SUB/CCD is associated with an application called CloneCD, MDF/MDS associated with Alcohol120 and BWT/BWA with BlindWrite.
Copy Protection
It doesnt take a lot to see why software companies would like to implement anti-copying schemes however from the consumer's perspective, it's not hard to see that discs are not indestructable and making a backup copy would be a wise thing. For the most part these protections are applied to games however applications feature them from time to time (although applications tend to focus in a different direction). Some of the more common protection schemes for (for DataCD and DataDVDs) are:
- ProtecCD. VOB's ProtectCD is a very cost effective way to provide copy-protection and integrate it with installation scripts: you can detect this scheme by opening the main exe with a hex-editor and searching for "VOB". Some games featuring this are Jet Fighter 4, Motoracer 2, Quake 3 Team Arena
- SafeDisc (aka SafeDisc v1, SafeDisc Lite) This is an extremely popular protection scheme because it doesnt require any changes to average computer hardware to function: the protection scheme works by verifying a digital signiture embedded into the disc. The main executeable is split across two files, an EXE and a ICD (the EXE essentially being a loader for the encrypted EXE stored inside the ICD). Due to it's age, this is a very easy protection scheme to bypass. Some games featuring this protection include: Army Men 2, Rainbow Six, Falcon 4 and Tiberian Sun. Ironically Encarta 2000 features this as well.
- SafeDisc 2. Although this should really be split into two categories (before- and after-SD2.4), SafeDisc2 extends upon SafeDisc v1 by integrating the EXE and ICD together into the EXE as well as adding an excessive number of read errors in the first 10,000 sectors of the and introducing 'weak sectors' Whereas the read-errors may prove to be a nuisance the weak sectors prove to be a very robust protection mechanism as it requires that the burner trying to perform the backup to have certain characteristics. Some games featuring this are Aquanox, Battlefield 1942, Red Alert 2 and Need For Speed Hot Pursuit 2
- SafeDisc 3. It was with this protection that really separated the exceptional drives from the very-good ones. SafeDisc3 supports some very robust encryption routines and allows for executeables to be encrypted across several CDs as well as introducing anti-virtual drive mechanisms (although in 90% of cases where people complain that they have problems with their virtual drives is because they've not looked deep enough ... SafeDisc3 allows for games to be run off virtual drives -- as long as the game is authenticated with the original copy first. Games like Prince of Persia Sands of Time, MOHPA and Doom3 pack this protection
- SafeDisc 4 Yet another incarnation of our favorite protection scheme and adds extensive blacklisting of virtual drives and methods. Some games featuring this protection are Cold Fear, Brother in Arms: Road to Hill 30, Silent Hunter III, Settler's Heritage of Kings and Prince of Persia Warrior Within
- SecurROM v1-v3 SecuROM is a popular alternative to SafeDisc and traditionally has been much more difficult to deal with. At the core, an each game is given a specific fingerprint which is verified by the executeable (allowing the executeable to essentially detect whether it is being run off a CDR or a pressed-CD).
- SecurROM NEW v4 It was this revision of SecuROM that separated the good drives from the bad ones as well as those in-the-know from those not. SecuROM v4 added a physical signiture property (think of it as a data densitiy measurement) as well as the ability to perform limited on-the-fly cd-checks (i.e., say the beginning of every level or something). Games featuring this include Empire Earth, Unreal 2 and UT2003
- SecuROM 5 This 'adds' some blacklisting for virtual drives as well as adding more level-checks and such, difficulty-wise there isnt a world of difference between SecuROM 4.8+ and SecuROM5. Some games featuring this include UT2004, Polar Express, Evil Genius and Full Spectrum Warrior
- SecuROM 7[/i]. Not a whole lot is known about this protection scheme but it seemed important enough to skip v6. Installing a SecuROM 7 game does usually entail also installing a system service (hence some/all of them require/'suggest' you restart the system). The name of the service is UAService7.exe (not sure whether or not this interferes with playing the game). Some games featuring this are Project Snoblind, WarChess, Act of War Direct Action and Constantine. It does look however that SecuROM7 is turning out to be the 'new StarForce'
- StarForce. Coming in three versions (Professional, CDR, Shareware) the most popular (CDR) is for all intents and purposes the be-all, end-all of protection mechanisms and isnt copyable short of a bit-burner (if you have to ask what those are, you wont be able to afford-one/know-what-to-do-with-it (and even then im not sure if you can). StarForce has also blacklisted damn near every virtual drive available as well. Some games featuring this impressive protection scheme are Silent Hunter III, Blitzkreig Rolling Thunder, Bandits Phoenix Rising, Beyond Divinity, Breed and Pax Romana.
Virtual Drive
Essentially this refers to the mechanism/software that allows you to be able ot use a CD/DVD image like it was a real disc. This offers a few benifits: (a) you dont have to waste a disc to see if something works (b) load times from harddrive are faster than from optical drive and. Most applications designed for backing up protected media come with some form of virtual drive as does Nero (although with very limited functionality).
Overburning
This refers to the process of burning more data (i.e., DataCD or DataDVD) than is originally specified -- some CD/DVDs handle it better than others.
ASPI, Pattin-Couffin
ASPI (Advanced SCSI Programming Interface) is just essentially a 'driver' that lets you interact with your optical drive the way it's supposed to. An improperly installed or configured ASPI layer can result in a whole slew of random problems. A more advanced version of the ASPI layer, called Pattin-Couffin allows better access to optical drive function by supported applications (say DVD43 or BlindWrite). If your application gives you the option of utilizing a Pattin-Couffin driver, take that option.
Buffer Underrun
When burning a disc, for all intents and purposes, "once the laser is on, there's no turning it off (until the disc is burnt)" What this really means to the end user is that "if they dont want their CD/DVD to get ruined, make sure the burner has a constant supply of data". Now this isnt always possible: user's tend to do things while they're burning and as such the steady flow of data is inturrupted. A simple countermeasure to this is to provide a bit of memory so that when the flow is interrupted the burner just uses the data stored in this memory to continue burning (hopefully that memory, or buffer, will be refilled before it runs out). Buffer sizes range from 512K to 8MB and even the 'massive' 8MB buffers only offer a second or two at most of protection. When this buffer runs out, an error known as a buffer underrun is generated and the CD/DVD is toast. That's where an innovative idea came up to "pause burning" as the buffer refills itself and resume once it's full. This idea is known buffer underrun protection (also going by a crapload of different names). Technically speaking, there are two revisions of this technology however all modern drives feature the second of the two (the more advanced) so it's not that important a distinction.
Firmware
The firmware on your optical drive defines that drive's capabilties and with some drives (more common with better drives), you can "upgrade" or flash that firmware to fix known problems, add fuctionality or increase performance. In some cases, a firmware flash is a method to kinda "reset" the drive if you've got some problems with it. Unless you've got a specific reason
not to, you should always keep your firmwares up to date
EFM aka Sheep
EFM (eight-fourteen modulation) refers to a drive's ability to properly translate an 8-bit byte to a 14-bit byte. The reason this is done is important is (a) at higher speeds, the laser has less and less time to determine if something represents a pit or a flat (0 or 1) and by making the scanning size bigger (to 14bits) there is less of a chance of error (the rule of EFM is to ensure that there are at least 2 zeros and no more than 10 between any pair of 1's) and (b) when making 1:1 backups of protected media (in particular anything protected with SafeDisc2 or better), hardware support is crucial. Back in the days when CloneCD was popular/useful, the ability of a drive to properly perform EFM was measured as an index of sheep (since the CloneCD mascott was a sheep):
- 0 Sheep = The drive cant do any EFM worth crap even to save it's life
- 1 Sheep = Quite common amoung "average" drives and the drive is able to do EFM most of the time
- 2 Sheep = Common amoung performance drives and indicates drives that can do EFM all the time evertime
- 3 Sheep = very rare!
Here is a little set of tests that allow you to determine the sheepcount of your drive.
Bitsetting and Booktyping
Due to the dual-standards with the DVD industry, there have been techniques established in order to maximize compatability of burnt media with the arbitrary drives. You can read more about this
here
Lightscribe
Lightscribe is a technology that allows you to impress a label or image onto a specialized disc thus creating an elegant label for your media without relying on markers or stickers etc.