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OPTICAL DISKS John Goodwin Optical Disks - CDs, DVDs, and Blu-Ray Why Optical? Information is both recorded and read using a laser light-beam. On recording, reflective material embedded within a plastic disk is melted to cause ‘pits’ in the recording surface. The reading process senses the presence of the pits. On rewritable materials, the surface may be ‘repaired’ by re-melting, and writing again. Magneto-Optical Disks Such appear to be very similar to ‘normal’ optical disks such as CDs & DVDs, but are quite different - and are encased in a caddy. The data is actually stored magnetically, but is read/written optically using a laser beam. Their use has not found favour generally in Europe, but these are still used for data in Japan. Consequently, I shall not be addressing these in general – apart from the SONY audio mini-disk system. CD & DVD Concepts Essentially, ALL 5.25 inch Optical Disks are very similar; the principal difference lies in the amount of data that they can hold – and this relates to the density in which they are written, and the ‘neverseen’ control information at the start of every disk Information is stored digitally in a series of ‘pits’ burnt into the media. Formats used by PCs and MAC are different; I shall not address MAC usage, but will mention audio CD players and DVD players, etc. Games machines use similar disks, but with their own proprietary formats, differing from other formats to deliberately prevent their use elsewhere. MAC Disks may be read on a PC using the programme ‘MAC-Drive’. Unpublished Information The differences between various types of Optical Disk are rarely explained adequately, and software rarely included with a PC (as sold) to handle all the different types. This is because these disks are largely proprietary formats, where the manufacturers have deliberately withheld information that enables access to the data. In File Manager, you will never see a full representation of what a data disk, film DVD, CD, or games disk contains. The situation is not entirely unlike that on hard disks, except that the information on the ‘hidden’ content has been published freely, there are programmes readily available to both read and amend the content, but there are no ‘extra bits’ of information secreted-away. Lead-in and Lead-out Areas The unpublished information is held in two separate areas – a lead-in area, and a lead-out area. The 1st lead-in area is at the logical start of the disk. Although I have read nothing specific of it, logic decrees that the combined space allocated to both areas is about 50 MB on a CD, and 500 MB on a DVD. The lead-in area (1 per session) contains the VTOC for the disk, and an area where the record of EoLFHS Computer Group -1- November 2011 OPTICAL DISKS John Goodwin usage is maintained – so that ‘deletions’ may be tracked. Nothing much is ever published as to the rest of the content; the lead-out area is located at the logical ‘end’ of the disk or session (the ‘outer’ tracks). The ‘Lead-out’ appears to be just a confirmation that the disk is complete. Disk ‘VTOC’ & ‘Multi-session’ The ‘standard’ way of writing to an optical disk, is to write the ‘entire’ contents in one continuous operation – known as a single session. This may contain ‘files’ – or be a disk ‘image’. Recent models of disk writer can write further ‘sessions’ at a later time – provided that the disk hasn’t been ‘closed’. The disk is ‘closed’ when the normal ‘VTOC’ is written, but when using ‘multi-session’ facilities, one VTOC for the 1st session is written into a temporary file, that allows the writing process to be continued later; further temporary VTOCs are produced for each subsequent session added. The operation that ‘closes’ the disk writes the latest VTOC into the normal VTOC area, after which further files cannot be added. ‘Unfinished’ disks do not have a VTOC in the conventional place – so are not readable by older single- session CD/DVD writers – or by any CD/DVD device that is read-only , as these do not normally search for the existence of a ‘temporary’ VTOC. One possibly unexpected snag with producing ‘multi-session’ disks, is that it is not possible to use the same file name in more than one session. Blu-Ray and HD disks These are relatively new formats, but are essentially very similar to CD and DVD. As some of the terminology differs slightly, to simplify the presentation these disk types will be covered in a separate section at the end of the presentation. Blu-Ray is so named, because the colour of the light in the laser beam is blue, whereas for the earlier types of disk it is red. The density of packing and deliberate format differences, prevent the disks from being used on other non-specific drives. ‘Burning’ a CD or DVD The process of ‘burning’ a CD or DVD involves directing a laser beam onto the recording medium, and causing tiny patches of it to be melted – thereby causing a depression (a ‘pit’) in the recording layer that can be sensed by laser light. In a re-recordable disk, the medium can be repaired by re- melting, then used again. Types of CD & DVD There are four major differences in the nature of the recordable disks. 1. The CD/DVD type in terms of its’ recordability – re-usable or not i.e. ‘R’ or ‘RW’. 2. The format in which the material is written to the disk – the disk ‘layout’ – (ROM, +, -, or RAM). 3. The quality of the material from which the recordable layer is made (shewn by the ‘colour’) 4. Whether the recording material is single, dual-layer, or multi-layer. There are differences of a rather technical nature that concern the FORMAT of a disk and how the data is actually represented physically on the disk. I shall relate the practical issues of the different types – but not the technical differences:EoLFHS Computer Group -2- November 2011 OPTICAL DISKS John Goodwin ROM, +, -, and RAM Another variation that I have not mentioned yet, is the difference between commercially made and ‘home’ recorded disks. (ROM and ‘other’ types) Most commercially made CDs and DVDs are ‘printed’ – not burned.; these are the CD-ROMs & DVD-ROMs. There are NO CD+ROMs or DVD+ROMs To create a CD or DVD at home, a writeable type of disk is required. – such as the ‘R’ or ‘RW’ varieties. Once finished, the disk becomes ‘read-only’, with the exception that files on both disk types can be marked-up as ‘deleted’ and will then become inaccessible by regular means, but ‘RW’ disks may be totally erased and re-used from scratch. CD-Rs and DVD-Rs are very cheap to produce, and can be read by ‘ALL’ CD and DVD drives of their appropriate type. (Of course, the older types of drive are for CDs only, and are therefore not capable of reading any DVDs). Once a CD or DVD has been created, it can be read without requiring special software - if it’s the type of disk that the drive the drive supports. Recording formats of blank disks (1/3). Disks are available in the following formatsCD-R, CD+R, CD-RW, CD+RW, DVD-R, DVD+R, DVD-RW, DVD+RW, DVD-RAM. (‘-ROM’ ones are available to users as pre-recorded only). The exact nature of the differences between each of these is beyond the scope of this presentation. It must suffice to know that different models of recorder will work just with the types of disk that they were designed to use. You MUST buy the correct type to use with YOUR recorder. Plus (+ ) or Minus (- ) e.g. CD- R or CD+ R are totally different formats. Technically, the ‘plus’ format is better – but more users have the capability of reading the ‘Minus’ format. (All Blu-Ray are + ). It’s rather like the ‘old’ problem of VHS, Betamax, and Phillips 2000 all over again with video recording tape! Note that ALL of the blank disks come pre-formatted – with their particular flavour of format predetermined and unchangeable. The ‘plus’ or ‘minus’ indicates the basic format method, and the ‘R’ or ‘RW’ shewing whether the disk is capable of re-use or not. However, some processes cause a secondary format to be superimposed Limitations with recorders. Be aware that with certain models of recorder – particularly the older models – that disks (of ANY type) created by them may not be readable on any disk drive other than the one that wrote them – even other specimens of the same type of equipment. The ‘RW’ disks are particularly critical; some recorders will not read ‘RW’ at all. More recent models of drives are much more compatible with each other. DVD recorders and readers are all capable of writing and reading most CDs of the appropriate types, but CD equipment will not handle DVDs at all. EoLFHS Computer Group -3- November 2011 OPTICAL DISKS John Goodwin The Physical Drive on Your Computer Most recently made computers, come with an optical disk drive that can read - and perhaps also write - all modern forms of optical disk – except Blu-Ray and HD. Only the specifically-enabled equipment, can handle Blu-Ray OR HD (rarely both) – but HD is obsolete. Older disk writers may handle just specific types of format – ‘+’ OR ‘-’. You may need to refer to the printed specification for the drive to find out which type applies. Programmes such as the Roxio ones can report the characteristics of each drive. If the drive supports re-writable disks, that information is generally marked on the drive itself. Optical Disk - Equipment Drivers All CD/DVD readers and writers require a software driver to make them function. The basic drivers FOR READING DISKS are either supplied with an external drive on a separate ‘drivers’ disk, or are already supplied with the Operating System on the PC – or in the case of a new computer - on an additional drivers disk. However, your equipment may be capable of performing standard WRITE and more advanced operations using other types of disk, but will require other drivers that are available only by purchasing specific proprietary software. There is often no warning of this. Your PC MAY come with a programme that can write a back-ups of sorts to an optical disk, or may have the Adaptec ‘Drag to Disk’ programme to use the optical drive as a RAM drive – but his is generally all that will be supplied. This is rarely explained to the purchaser. Types of Disk – Type R The suffix ‘R’ applies to a ‘write once’ disk. (WORM) This description can be rather misleading, as the disk can be written to many times if appropriate. What it really means is that a particular disk area can be used just once. ‘Closing’ or ‘Finalising’ a disk prevents anything further being written, but until a disk is closed, ‘multi-session’ disk writers can add further data provided the disk is not full. It is also possible to mark files as ‘deleted’ to make them incapable of further access by normal means. Each ‘session’ has its’ own directory structure. Older equipment was capable of writing single-session disks only, that were ‘closed’ after writing for the first and only time. Types of Disk – Type RW The RW disk type may be used in exactly the same way as type R, but additionally the disk may be ‘erased’ and the whole surface used again for 100 or so times. (Eventually, the disk will fail!) A re-writeable disk may also have a secondary format applied that enables it (with an appropriate driver) to be re-used just like a hard disk or other removable magnetic or ‘optical’ disk drive. This is like a ‘RAM’ drive, but is technically different from the commercially available ‘RAM’ disks. Types of Disk: DVD+/-RW, DVD-RAM, double-sided, & dual layer DVDs A re-writable DVD can be used in the same way as a re-writable CD. However, there is also a separate ‘RAM’ category that is quite different in technical format, serves the same purpose, but is more robust; these are often sold in (open-able) cassettes (disks will fit a standard drive). EoLFHS Computer Group -4- November 2011 OPTICAL DISKS John Goodwin Not all drives support ‘RAM’ usage It is possible to get double-sided DVDs, but these are generally the RAM variety – or commercially made read-only disks that are two thin DVD-ROMs glued back-to-back. (It’s a ‘cheat’ to give 17GB disks). Certain DVD writers are capable of recording almost twice as much data by using a second layer physically located deeper that the standard layer on specially constructed disks marked ‘dual layer’ disks (or ‘DVD 9’). The recording layers The best CDs have a GOLD base. (NOT Yellow coloured!). It is recommended that such CDs be used for archival copies of photographs etc. For safety, make two copies, and store each in separate buildings. The next best category have a silver base. The cheapest disks use a blue, green or yellow di-azo base, and are very variable in quality. Avoid – or buy only recognised brands. CD/DVD usage The most obvious usage is for long-term storage – such as for backing up the system, or for data. They have the added advantage that they cannot be wiped by military aircraft scanning whilst they pass overhead, but of course should always be stored ‘off-site’ to guard against fire, and more than one copy be available. (DON’T use ‘RW’ types – they may fail when least expected). Specialist storage usage includes DVDs of home videos, CDs of music – perhaps copied from vinyl, and photographs. MP3 format CDs & DVDs for audio are the latest development. CD/DVD ‘Types’ (1/5) Irrespective of the basic disk type (R/RW etc) information is recorded onto a CD in one of about 10+ different ‘layouts’; these are referred to as e.g. Red Book, Green Book etc., or generically as the ‘Rainbow’ Books, that define the layouts. The different nomenclature denotes the ‘purpose’ of the disk – e.g. general data, music, Video CD, CD-I etc. The ‘Rainbow’ Book names (see below) are nothing technical They refer to the colour of the COVER of the binder that contains the specification of the disk type – as defined by Phillips & Sony that jointly developed the present CD and DVD optical disk formats ‘Rainbow’ Books Red - Original ‘Audio’ CD-ROM – with text added later Yellow - CD-ROM with extensions Orange - Magneto-optical, CD-R & CD-RW, and introduced multisession writing Blue - CD Erasable enhancement including graphics for Karaoke Green - CD-i Interactive White - Video – VCD and Super VCD etc Beige - Photo-CD EoLFHS Computer Group -5- November 2011 OPTICAL DISKS John Goodwin Scarlet - Super Audio – SACD Purple - Double Density CD Black - Other (No ‘Rainbow’ Book) – DVD + Blu-Ray etc Certain of these 10+ types can be read only by (fully-fledged) computer. Standard audio types are playable on a CD player, but any (lead-in or data area) text and data tracks contained are normally ignored. Video CDs are sometimes playable on DVD players, and of course on specific Video CD players sold in the Far East. CD-I’s and Photo-CDs play on special equipment, or using special software on a PC. It must be noted that to be accepted as one of the standard types of disc, the data must appear on it in exactly the prescribed format, including file-types. As an example of where things don’t work out, is where visual material is stored in the ‘AVI’ format; this isn’t recognised by DVD players – so the disk is treated as erroneous, but may be read and played using appropriate software on a computer. Data & Programme Disks CDs & DVDs may be used to hold just ‘simple’ data, or computer programmes etc. Data CDs are ‘Orange book’ format, but DVDs have no specifically named format. Disks containing programme material may be made ‘bootable’. This is done by including certain settings in the unseen lead-in area; sometimes, this causes the execution of programmes that are visible within the normal data area. The ‘boot’ code is actually executed from entirely within the lead-in area; this often (but not always) executes a ‘normal’ programme from the data area. You cannot tell whether a disk is bootable or not just by looking at the data in File Manager. Sometimes a disk cannot be started just by clicking on a programme name – the full auto-run procedure has to be invoked. Optical Disk Control Information The ‘book’ format definitions specify all manner of information to be stored in a separate area (the lead-in) at the beginning of each disk that is never seen by the user. This can be just text, or information about what is to be found elsewhere on the disk, and even full computer programmes. A regular ‘copy’ of a CD or DVD always omits ALL of this specialist information, thereby disabling certain features that were present, and whose absence may cause the copy-disk to be totally useless for the purpose intended. What you can see on an optical disk when examined in ‘File Manager/Explorer’, are merely the simple ‘data’ files from the ‘body’ of the disk; the ‘control’ files are never displayed. DVD Types DVD disks types are not named like CDs. These fall within the ‘Black Book’ category DVD- RWs can be either the ‘special’‘VR ’ format or normal ‘Video ’ format. Most DVD writers support just the ‘normal’ ‘video’ format. The ‘VR ’ format is capable of limited editing – e.g. Trimming off superfluous material and inserting ‘Menus’ Recording life-time EoLFHS Computer Group -6- November 2011 OPTICAL DISKS John Goodwin When the first commercially-made read-only CDs were marketed, it was claimed that they would have a life of 10 years. I still use ones purchased 33 years ago! For recordable disks, buy only proprietary brands that offer a lifetime guarantee. There are some disks available whose ‘life time’ may be measured in hours. The life of ‘the best’ disks is now 70 years. Burning a CD or DVD There are now many programmes available to do this, but the acknowledged experts on the production of these disks are Roxio – that was formerly the software division of Adaptec. Roxio market two products that seem to cover the same ground – but differently. WinOnDVD is the simplest, and handles the bit-by-bit copy process well. Easy Media Creator 2012 Ultimate has comprehensive facilities to author all the various types of disk. The ‘Easy Media Creator’ product incorporates all the drivers for CD & DVD RAM etc. (plus BluRay and HD as an extension). NERO is another popular programme to write disks Copying CDs Any CD that can be read, can be copied – but the copy won’t necessarily work. Music CDs, CDI’s, & PhotoCDs are usually not a problem, but often special CDs are copy-protected by various devices that prevent a file-by-file copy from installing, and may also contain ‘invisible’ information at the start that does not get copied (including any Audio album name and track names). Another type of device that may be used to disable copies, is to include a deliberate error in the format, or to write vital information outside the ‘normal’ data area. Using WinOnDVD to do a bit-by-bit copy overcomes most difficulties, but Sony Playstation-I disks require a CPU replacement to enable reading a copy disk. DVD Copying Essentially, DVDs are simple data disks, so generally copy with no difficulty (if you can display the data); some include a ‘copy protection code’. There are special programmes available to facilitate the process (e.g. DVD X Copy). ‘Film’ DVDs contain a ‘region’ code that may prevent a disk being read/played on a player designed for use in a different part of the world. ‘DVD X Copy’ and other programmes allow the region code to be altered on the copy. Sony Playstation II uses ‘protected’ DVDs Film-DVD Region Coding (¼) Although commercially made disks cost a mere twenty pence or so each to produce, Marketing thieves like to sell film-DVDs at grossly excessive prices, and to vary the prices substantially in different parts of the world. They try to prevent disks sold in one area from being used in another, by the addition of ‘region codes’. They claim – fraudulently – that the code is related to the ‘release’ of films at different times. Film-DVDs sold within Europe normally carry the Region Code ‘2’ – unless a ‘documentary’ etc. when they carry a ‘region free’ code (zero or nine, and 6.7 8). The code is almost always marked on the packaging. Unless the code is compatible with that in the firmware of the DVD drive, AND the EoLFHS Computer Group -7- November 2011 OPTICAL DISKS John Goodwin Operating System, AND the application programme – the disk will not be processed and played. Dedicated DVD players have the code merely in the firmware of the drive, but check this to the disk concerned. On computers, the Operating System will permit the user to change the Region Code setting in both the Operating System AND the DVD drive, a maximum of five times. In practice, this facility is of use merely to change a drive setting for the initial set-up to facilitate using disks solely of the ‘one’ type that the user already has. The DVD drive or player will just ignore any disk having the ‘wrong’ code – without ANY diagnostic messages! It is theoretically possible to get your existing DVD player ‘zapped’ to play ‘all regions’ (charge about £70), but it may be possible to get retailers to ‘fix’ new purchases at no extra cost, or the user to apply instructions from the Internet using the standard user remote control unit, or by hiring an ‘engineer’s’ remote control unit. For computers, the programmes ‘Any DVD’ and ‘Region Free’ can be obtained over the Internet, and these left running on the PC to enable all DVDs to be read, and provide other functionality as well. Film DVD Markings Film DVD-ROMs may carry a further marking that reflects how they have been made; these codes are ‘DVD5’ and ‘DVD9’. These relate to whether the disks are Single or Dual Layer. DVD5 denotes a 5 GB (4.7 GB) disk. DVD9 denotes a 9 GB (9.2 GB) disk. Older players may not cope with DVD9. Most modern film disks are DVD9 regardless of content. The second layer isn’t necessarily used – it just depends on how long the film is. Video-CD and Super-video CD These formats are similar to DVD, but lower quality, and now therefore considered by many people to be obsolete. Video-CD is the video format used extensively in the Far East, because these disks are available much cheaper than (legal) Film-DVDs. Most DVD players sold within Europe don’t support these formats; buying a doctored DVD player in the Far East is a cheap way of solving various problems. General Purpose Players DVDs, Video-CDs, and Super- Video CDs will play on stand- alone players or player-recorders of the appropriate type. These players contain programme code to process just the disks of the type for which they were designed, and cannot be updated. All these disk types will play on a modern computer, using software such as PowerDVD or WinDVD, provided that the disk drive supports the basic format of the disk. Music CDs & Text? Music CDs were the first type of CD to appear – back in 1978. Essentially, these are covered by the ‘Red Book’ definitions – but an extension was added for the inclusion of Track Names & CD Text, such as Album Name, Track Titles, genre, etc. Unfortunately, this text information is held quite separately in the ‘Lead-in’ area of the disk, and this is not processed by most audio players and many Optical Disk writers. Most computer programmes EoLFHS Computer Group -8- November 2011 OPTICAL DISKS John Goodwin display only the conventional track names for ALL CDs, with these always in the form ‘Tracknn01’ for music CDs – so the name details of the music content remains unseen – if indeed present. This can be confusing for a user that has generated a Music CD from his own audio source, and carefully entered all the track names, only to wonder why these do not shew-up on the finished disk! The reason relates to the ‘old’ file-names of ‘8.3’ structure – versus ‘long’ file names.. Very few home and in-car audio players actually display the ‘extended’ CD Names. Sony Sonic Stage and Apple i-Tunes will display the names if present on a CD, and have a facility to retrieve names from Sony’s GraceNote database. GraceNote This is a facility now acquired by SONY, to store and retrieve Album Names and Track Names for CDs. Most commercially made disks do NOT contain this data, but when played on an Internet connected computer using GRACENOTE, the names may then be viewed and stored. The same database may be used to retrieve the names for albums transcribed at home from sources such as vinyl records and pre-recorded tapes, or any digitised copy of commercially recorded material. The system recognises the ‘fingerprint’ of the recorded music. CD Interactive (CD-I) This format supported simple games, dictionary look-ups, and so on; originally, a dedicated CD-I player was required. Now obsolete within Europe, Far East DVD players generally support this and virtually all other formats. Photo-CD This format and dedicated player, was introduced by Kodak for holding digital images, and presenting slide shows of them. The slide-show feature won’t work on the disks unless the dedicated player is available, but the images are still accessible. Far East DVD players generally, and some PC software, still support the format. Film DVD – VR When recording a film onto a re-writable DVD, some equipment supports a choice of two formats – the ‘normal’ one and a ‘VR’ format. When the ‘VR’ format is used, it is possible to subsequently edit the recording within the recorder to delete scenes and add menus. Not all players support the VR format. Mini CD Disks of diameter about three inches, and those in the general shape and size of a business card are available in the CD-R format, as a gimmick, or for mailing purposes. I’ve had a couple supplied with new equipment, containing the drivers. These aren’t recommended, as they don’t work with all equipment; obviously they can’t be used with some players mounted vertically. Mini Disk – MD & Hi-MD This is a format that doesn’t fit in with the rest of the CD/DVD range, because it’s actually magneto-optical. It was intended as a more portable replacement for Audio CDs, but can attach to a computer and can hold general data. To some extent, it’s been superceded by MP3 players, but not entirely as cartridge disks are interchangeable. Pre-recorded music was available in this form. Disks of both 80 minute and 1 GB sizes are available. Special software is supplied with the units. EoLFHS Computer Group -9- November 2011 OPTICAL DISKS John Goodwin Players discontinued end September 2011. 17 GB DVDs? When DVDs were first announced, it was claimed that they could hold up to 17 GB of data. This is not exactly true. A standard DVD can hold up to 4.7 GB (DVD5). Dual layer disks (DVD9) hold double that. Greater capacity is achieved by a cheat – two thin DVDs are cemented back-to-back after creation! I have two ‘sandwich’ DVDs with one film on each – the PAL and NSTC versions mounted back-to-back; not really of much use normally! PAL or NSTC DVDs Film DVDs are mostly recorded using the PAL video recording system. Even France has now abandoned SECAM, but in North America the NSTC system is still used. Most recent DVD players and computers accept disks of either system, but some older equipment plays PAL only, and some do include NTSC –but play these solely in Black & White. Blu-Ray, HD, and 3-D For all practical purposes, these are just higher capacity DVDs, but produce video in a higher definition – just for those that really care about the difference and are prepared to pay for it. To use Blu-Ray - or HD (High Definition)? It’s a throwback to the fight between VHS, Betamax, and Phillips 2000 etc. Blu-Ray has won, thanks perhaps to Sony Playstation III. 3-dimensional versions of film are now appearing on Blu-Ray only. Blu-Ray Blu-Ray requires a different type of disk reader/writer to simple CD/DVD drives. Such Blu-Ray drives are not generally compatible with HD, and HD is not compatible with Blu-Ray, but BOTH drives are backward compatible with CD & DVD. Older drives were single-layer 25 GB, whereas the latest are dual-layer 50 GB – but neither usually marked clearly as such. Multi-layer (10) disks have been proposed, but so far have not appeared. Presumably a new player/recorder would be required. Blu-Ray disks come in four types – The BD-R write once type, and the BD-E (E=erasable) re-writable type. Each comes in 25 GB – single-layer – and 50 GB – dual layer – types. There is apparently a Mini version as well. There are no ‘plus’ variations The disks are currently VERY expensive - £24+ for 50 GB and £5 for 25 GB - but prices falling. If capacity not shewn 25 GB. Due to the price, and high probability of errors in the writing process, the write-once ‘R’ type are not economically viable! The Blu-Ray system is rather expensive to buy-into, and its’ benefits somewhat questionable DVD films played on high quality equipment including a high-definition television, are - to me – indistinguishable from Blu-Ray versions Using Blu-Ray writeable disks for computer data is rather expensive – particularly when a mistake occurs; DVDs are virtually expendable EoLFHS Computer Group - 10 - November 2011 OPTICAL DISKS John Goodwin Blu-Ray Region Codes These are differently coded to DVDs, and the checking system is quite different. There are but three region codes – A, B, C. Europe is ‘B’. The region code is held on the disk itself, AND also on the player. The code on the Blu-Ray player, may be zapped in a similar manner to a DVD player. Multi-coding occurs. On computers, the region code for Blu-Ray is hard coded into the SOFTWARE itself – so you require to purchase a programme sold for the region that applies to the disks purchased. The software programmes ANYDVD and Region-Free haven’t attempted to address this issue! Labelling User-produced Optical Disks Finished disks require labelling, but this must be done on the ‘top’ surface only – generally using a special marker pen. Under no circumstances may regular labels be stuck onto any part of the disk – to unbalance it; special circular labels are made to cover the entire surface. Stand-alone printing devices may be used to label a disk, but some printers have been designed to print directly to the CD surface Special Disks for Printing Most ‘blank’ Disks have surface markings for the brand etc., but have an area marked-up to hold a descriptive legend for manual completion by pen. Some makers offer disks that have the top surface entirely blank – to facilitate printing with lines of text – and/or a picture, using a suitable printer. One type of disk known as ‘Lightscribe’, has the top surface coated with a substance that when used in a specifically ‘Lightscribe-enabled’ disk drive or printer drive, can produce a coloured picture etc. using a laser on that surface without requiring conventional inks. THE END © John I. Goodwin, 2011 EoLFHS Computer Group - 11 - November 2011