Chief Surveyor General - Projects: Digital Lodgement

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Electronic Media Investigation

Factor	Tapes	WWW	FTP	E-Mail	CD's	Stiffy Disk
Device Access	Slow --The device can be slow in retrieving just 1 file. This can take 2 minutes.	The spread of gopher sites is no doubt due in large part to its ease of use and the embedded link structure that makes "tunneling" through the Internet from one source of information to the next, but it require ongoing maintenance and vigilance.	Low cost to develop. Virtually universal, low cost access to users	Depending on the system that you use, but it can be fast.	Various speeds available from 4x in the beginning to 56x today for read and writing about 8x.	Instantaneous, but not as fast as harddrive.
File Access	Slow -- you have to get to where the file is on the tape, which may take several steps, and then use some processor to copy it to disk. If you need more than one, you may have to rewind the tape to get the second one.	Instantaneous, but the downloading of the files may take up to a few minutes.	Same as WWW.	Same as with WWW.	Almost instantaneous	Instantaneous, although a noticeable difference exist between a stiffy and harddrives as well as CD drives.
Security	Iffy -Internally labelled tapes can protect unauthorized access, but unlabelled tapes can be mounted by anyone.	Very secure - secure protocols, IP barring, restrictions, but it can be accessed by unauthorized persons.	Same as WWW.	Depending on the system settings; anything can be sent by e-mail. The system must just be protected by passwords and the data can even be encrypted.	You can lock a removable platter away and protect it with passwords or encryption.	Secure - no one can get to your disk unless you set up an access password for it. Further it is the same as mentioned with the tapes.
Safety	Tapes must be handled and exposed to the air. Damage can occur which destroys files and may be sufficient to prevent any data access. And there's always the possibility with tapes not labeled private or a wrong-tape mount (by you or someone else).	No particular safety precautions.	Same as WWW.	Same as WWW.	The head crashes that can occur with magnetic disks do not happen with optical disks. Optical disks show a high tolerance against impact. It is pure, strong, and lightweight. Its structure is physically and chemically stable and exhibits negligible degradation over time. Protecting the media from external environmental factors.	The same as with tapes.
Portability	Excellent - tapes are easy to carry and easy to store, but keep in mind transit time and cost.	Not portable, but where there's a telephone line, there's WWW.	Same as WWW.	You cannot send e-mail without a telephone line, cellphone line, etc.	You can distribute a removable disk by mailing it; again remember the transit time and cost.	Also the same as with tapes.
Capacity	Large, expandable - up to 12G per tape; just get more tapes.	Depending on the size of the hard disk(s) used.	Same as WWW.	The service provider may impose limits.	Average of 650 megabytes.	Limited, expensive - the largest disk normally available is about 1.44 MB.
Cost	Cheap per meg - R0,02 per MB, R40 per tape (2G). If viewed in the sense of one tape - expensive, plus transit.	As with the e-mail plus service provider.	As with the service provider or if self owned.	Cost is mainly for the telephone bill which is approximately between R2,12 - R3,71 per MB. No post or transit cost. Service provider as with internet (WWW).	Cheap per MB - R0,02 per MB, R11 per CD (650MB)	Limited, expensive - each MB eats up R1,60 of account funds a month, and R2,30 per stiffy. Viewed with stiffy cheap, plus transit.

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