Imaging: Storage Requirements

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1 scanned page (8 1/2 by 11 inches) (CCITT G4 compressed) = 50 KiloBytes (KByte) (on average)

1 file cabinet (4 drawer) (10,000 pages on average) = 500 MegaBytes (MByte)= 1 CD ROM

2 file cabinets = 1,000 MBytes = 1 GigaByte (GByte); 10 file cabinets = 1 DVD (see below)

2,000 file cabinets = 1,000 GBytes = 1 TeraByte (TByte); 2,000 file cabinets = 200 DVDs

1 box (in inches: 12 wide x 15 long x 9.5 d) (2,500 pages) = 1 file drawer = 2 linear feet of files = 125 MBytes

8 boxes = 16 linear feet = 1 GByte; 8,000 boxes = 16,000 linear feet = 1 TByte

1 roll of 16 mm microfilm (100 ft) = 2,500 letter size images = 1 box = 125 MBytes

1 roll of 35 mm microfilm (100 ft) = 5,000 letter size images (or letter size image equivalents)

1 microfiche (average) = 100 letter size images;

200 fiche = 20,000 images = 1 GByte

N.B. In many record series, microfiche contain only a few images because each fiche represents a single record in the series. In this case filming breaks on records, rather than being continuous. To a lesser extent this is also true for roll film. In these cases, the amount of storage required depends on the number of images on the film, not the number of microfiche or the number of rolls of film. Scanned aperture card images require the same storage as the document or drawing in the aperture.

1 hour compressed color video = 2 GBytes (DVD, MPEG 2) (image quality dependent)

1 hour audio = 10 MBytes (dictation, answering machine) to 500 MBytes (a CD holds 74 minutes of music)

1 color picture = 10 KBytes (thumbnail) to 5 MBytes (for each of 100 photos on a 500 MByte photo CD)

The size of compressed file depends on the resolution (DPI: Dots Per Inch) and the detail (information) in the photograph. The detail in a photograph is dependent on the size of the negative and the quality of the film and the camera and lens (It is not related to the print size unless the print is smaller than the negative). The resolution of the scan should be chosen to match the detail of the photograph. For most cameras, films, and formats 35mm and smaller, the 5 MByte Photo CD format (3072 by 2048 pixels) captures all the information in the image.

This is in dots per image rather than dots per inch.

1 Chest X-ray (14 x 17 inches), = 1 MegaByte: 150 DPI (Dots Per Inch), 12 bits (compressed) (12 bits per pixel, provides 4096 shades of grey) (wavlet compression, lossless mode, has FDA 510(k) approval) / (150 DPI, 12 bit images recommended by American College of Radiology for primary reads) / 14 x 17 Chest X-ray =200 KiloBytes (for secondary reads: wavlet compression, lossy mode, has FDA 510(k) approval)

1 Byte (B)(common usage) = 8 bits (b) = 1 character; 1 Unicode Byte = 16 bits = 1 character

1,000 Bytes =~ (~ about) 1 KiloByte; 1,000 KBytes =~ 1 MegaByte;

1,000 MBytes =~ 1 GigaByte; 1,000 GBytes =~ 1 TeraByte;

1,000 TBytes =~ 1 PetaByte; 1,000 PBytes =~ 1 ExaByte

Modem = 28.8 Kbit per second = 2 pages per minute (~$30.00 per month for a standard phone line)

ISDN (1 voice channel) = 56 Kbit per second = 5 pages per minute (~$50.00 per month)(ISDN charge)

T1 (24 voice channels) = 1.544 Mbit per second = 3 pages per second (~$1,000.00 per month)

Ethernet (CSMA/CD) = 1 Mbit per second (effective) or 10 Mbit per second (nominal) = 2 pages per sec.

OC3 ATM (Asynchronous Transfer Mode) = 155 Mbit per second = 300 pages per second

OC192 (SONET optical fiber) = 10 Gbit per second = 20,000 pages (2 file cabinets) per second

Optical carrier frequency (1,300 nm) = 230 THz (about 20,000 cycles used for every OC192 bit transmitted)

1 DVD (Digital Video Disk) (same physical size as a CD ROM) = 7.4 GByte (WORM) (10 file cabinets) WORM:(Write Once, Read Many) (2 sided, 1 layer per side); = 5.2 GByte RAM (overwrite, rewrite) (2 sided, 1 layer per side); = 17 GBytes (ROM) (2 sided, 2 layers per side).

Multimedia: 5 channel (theater quality surround sound)(5.1, Dolby AC-3) / 96 KHz / 24 bit audio, 8 languages , 32 subtitles, and about 135 minutes (long enough to accommodate 94% of all movies) of high quality (720 horizontal lines) video on each of 4 layers. The file format is ISO 13346 UDF (Universal Disk Format) which harmonizes all CD recording standards including ISO 9660. Available in 1996. A future technology, 3rd generation blue lasers [sort of a blue light special], should yield a 40 GByte ROM for HDTV.

1 pulp tree (loblolly pine) = 1/10th cord of wood = 10,000 pages = 1 File Cabinet = 4 boxes = 1/2 GByte

1 lumber tree (20 inch diameter, 110 ft tall, 50 years old) = 1 cord, 10 pulp tree (8 in. dia., 50 ft tall, 20 yrs old) = 1 cord = 4 x 4 x 8 ft = 128 cubic ft (75 cubic feet of wood)

1 wordprocessor or OCR'ed (Optical Character Recognition) page = 5 KBytes (all pages listed above are scanned pages)

1 compressed page of COLD (Computer Output to Laser Disk) or COOL (Computer Output On-Line) = 1 KByte Minimum commercial scanning cost for backfile conversion (more than 1 million pages) ~ 5 cents/page