Disclosure to Promote the Right To Information

Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public.

इंटरनेट मानक

“!ान $ एक न' भारत का +नम-ण”Satyanarayan Gangaram Pitroda

“Invent a New India Using Knowledge”

“प0रा1 को छोड न' 5 तरफ”Jawaharlal Nehru

“Step Out From the Old to the New”

“जान1 का अ+धकार, जी1 का अ+धकार”Mazdoor Kisan Shakti Sangathan

“The Right to Information, The Right to Live”

“!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता है”Bhartṛhari—Nītiśatakam

“Knowledge is such a treasure which cannot be stolen”

“Invent a New India Using Knowledge”

है”ह”ह

IS 12223-2 (1989): Data Interchange on 6.30 mm WideMagnetic Tape Cartridge Using IMFM Recording at 252 ftpmm,Part 2: Track Format and Method of Recording For DataInterchange in Start/Stop Mode [LITD 16: Computer Hardware,Peripherals and Identification Cards]

IS 12223 (Part 2) : 1989 IS0 806312: 1986

. Indian Standard SPECIFICATION FOR DATA INTERCHANGE

ON 6.30 mm WIDE MAGNETIC TAPE CARTRIDGE

USING IMFM RECORDING,‘AT 252 ftpmm PART 2 TRACK FORMAT AND METHOD OF RECORDING

FOR DATA INTERCHANGE IN START/STOP MODE

UDC 681.327.636:621.798.1 l-52

0 BE 1990

BUREAU OF INDIAN STANDARDS MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG

NEW DELHI 110002

August 1990 Price Group 3

IS 12223 (Part 2) : 1989 IS0 8063/if;,lS86

Indian Standard

SPECIFICATION FOR DATA INTERCHANGE

ON 6.30 mm WIDE MAGNETIC TAPE CARTRIDGE

USING IMFM.RECORDlNG AT 252 ftpmm

PART 2 TRACK FORMAT AND METHOD OF RECORDING

FOR DATA INTERCHANGE IN START/STOP MODE

NATIONAL FOREWORD

This Indian Standard (Part 2). which is identical with IS0 8063/2 : 1986 ‘Information processing-

Data interchange on 6.30 mm (0.25 in) wide magnetic tape cartridge using IMFM recording at

252 ftpmm (6400 ftpi) - Part 2: Track format and method of recording for data interchange in

start/stop mode’, issued by the International Organization for Standardization (ISO) was adopted by

the Bureau of Indian Standards on 15 December 1989 on the recommendation of the Computers,

Business Machines and Calculators Sectional Committee (LTDC 24) and approval of the Electronics

and Telecommunication Division Council.

ln the adopted standard certain terminology and conventions are not identical with those used in

Indian Standards; attention is specially drawn to the following:

a) Comma (,) has been used as a decimal marker while in Indian Standards the current

practice is to use a point (.) as the decimal marker.

b) wherever the words ‘International Standard’ appear, referring to this standard. they should

be read as ‘Indian Standard’.

For the, purpose of this Indian Standard, only metric dimensions are applicable.

CROSS REFERENCE.S

ln this Indian Standard. the following international standards are referred to. Read in their respective places, the following:

Indian Standard Degree of

Correspondence International Standard

IS0 646 Information processing- IS 10315 : 1982 7-bit coded Technically equivalent

IS0 7-bit coded character set for character set for information

information interchange interchange

IS0 2022 Information process-

ing-ISO 7-bit and 8-bit coded

character sets-Code extension

techniques

IS 12326 : 1987 7-bit and El-bit Identical

coded character sets-Code ext-

ension techniques

1

IS 12223 (Part 2) : 1989 IS0 8063/2 : 1986

.

international Standard Indian Standard Degree of

Correspondence

IS0 4341 . Information process- IS 12660 : 1989 Specification for Identical ing-Magnetic tape cassette and magnetic tape cassette and cart- cartridge labelling and file struc- ridge labelling and file structure ture for information interchange for information interchange

IS0 4873 information process- IS 10401 : 1982 8-bit coded Technically ing-IS0 8-bit code-Structure character set for informatlbiif equivalent and rules for implementation interchange.

2

IS 12223 (Part 2) : 1989 IS0 806312 : 1986 _

1 Scope and field of application

IS0 8063 specifies the characteristics of a tape cartridge using 6.30 mm (0.25 in) wide magnetic tape for data interchange be- tween data processing systems.

IS0 2022, Information processing - IS0 Fbit and B-bit coded character sets - Code extension techniques.

IS0 4341, Information processing - Magnetic tape cassette and cartridge labelling and.file structure for information inter- change.

IS0 806311 specifies the dimensional, physical and magnetic characteristics of the cartrid&, and the track layout. IS0 4873, Information processing - IS0 Bbit code - Struc-

ture and rules for implementation. This part of IS0 8063 specifies the quality of the recorded signals, and the track format to be used on a 630 mm (0.25 in) magnetic tape cartridge, recorded at 252 ftpmm I6 400 ftpi) using IMFM recording and the start/stop mode of operation.

4 Data representation

Together with the labelling scheme specified in IS0 4341, IS0 8063/l and IS0 @X3/2 provide for full data interchange between data processing systems.

Characters shall be represented by means of the IS0 ‘I-bit coded character set (see IS0 646) and, where required, by its 7-bit or 8-bit extensions (see IS0 2022) or by means of the IS0 8-bit coded character set (see IS0 4673).

NOTE - Numeric values in the SI and/or Imperial measurement system in this part of IS0 6063 may have been rounded off and therefore are consistent with, but noi exactly equal to, each other. Either system may be used, but the two should be neither intermixed nor reconverted. The original design was made using the Imperial measurement system.

4.1 Recording of 7-bit coded characters

Each 7-bit coded character shall be recorded in bit positions 81 to 87 of an &bit byte; bit-position 138 shall always be recorded with ZERO. The relationship shall be as shown in figure 1.

IS0 8063 applies to cartridges used for data interchange. Where it applies for testing oniy, this is specifically stated.

2 Conformance

A 6.30 mm (0.25 in) wide magnetic tape cartridge shall be in conformance with IS0 8063 if it meets all mandatory requirements of both IS0 806311 and IS0 8063/2.

4.2 Recording of &bit coded characters

Each 8-bit coded character shall be recorded in bit positions 61 to I38 of an Sbit byte. The relationship shall be as shown in figure 2.

5 Recording

3 References 5.1 Method of recording

IS0 646, Information processing - IS0 7-bit coded character set for information interchange.

The method of recording shall be Inverted Modified Frequency Modulation (IMFM) for which the conditions shall be

Bii of the 7-bit combination

Bit-positions in the byte

0 b7 b6 b5 b4 b3 b2 bl

B6 87 B6 85 64 83’ 82 El

Figure 1

IS 12223 (Part 2) : 1989

IS0 806312 : 1986

.

Bits of the 8.bit combination

Bit-positions in the byte

b8 b7 b6 b5 b4 b3 b2 bl

88 B7 1 B6 85 84 83 j 82 1 Bl

Figure 2

1

Figure 3

a) a flux transition shall be written at the centre of a btt cell

containing a ZERO;

5.4 Flux transition spacing

b) a flux transition shall be written at the cell boundary

between consecutive bit cells containing ONES.

54.1 Effect of asymmetry

See figure 3.

At nominal recording density the average variation of spacing

between consecutive flux transitions, taken over 32 flux tran-

sition spacings, shall not be greater than 2 % (see figure 4).

5.2 Measurement 5.4.2 Effect of data patterns

All stgnal measurements shall be made at the point in the read

chain where the amplitude is proportional to the rate of change

of flux in the read head. The ratio of tape speed to the surface

speed of the belt capstan shall be assumed to be exactly 0,76.

In each of the two possible sequences of flux transitions de-

fined by bit pattern OG6OOCQ1ooooooO10 the spacing dt

between the two ZERO flux transitions preceding the ONE bit

cell shall not exceed the average of the four earlier flux tran-

sition spacings by more than 12 %.

5.3 Density of recording

53.1 The nominal recording density shall be 252 ftpmm

16 400 ftpi). The nominal bit cell length shall be 3.97 urn

(156 f.tin).

Similarly, the spacing d2 between the two ZERO flux transitions

following the ONE bit cell shall not exceed the average of the

four subsequent flux transition’spacings by more than 12 %

(see figure 5).

5.3.2 The long-term average bit cell length shall be the

average bit cell length measured over at least 506 OOB flux tran-

sitions. It shall be within f 3 % of the nominal bit cell length.

5.5 Signal amplitude of the interchanged

cartridge

5.51 The average peak-to-peak signal ampfitude at

252 ftpmm (6 400 ftpi) shall not deviate by more than +$ %

from SRA2s2.

5.3.3 The short-term average bit cell length, referred to a par-

ticular bit cell, shall be the average af the lengths of the

preceding four bit cells. It shall be within f 7 % of the long-

term average bit cell length and shall be within + 2 % of *he

average bit cell length of any string of 128 consecutive bit cells

containing the said particular bit cell.

Averaging shall be done over a minimum of 6 400 flux tran-

sitions, which may be segmented into blocks

5.52 No peak-to-peak signal amplitude at 126 ftpmm

(3 200 ftpi) shall be more than three times SRA,,.

; IS 12223 (Part 2) : 1989 IS0 8063/2 : 1986

2 jF3’ldi 7 di+ll < oo2

ii c di+di+l ’ i=l

Figure 4

Id, - 025 D,l < o ,2 > Ia; * 0.2ykl 0.25 D, ’ 0,25 D2

Figbe 5

5.6 Minimum signal amplitude

No cartridge, when interchanged,’ shall contain flux transitions the base-to-peak amplitudes of which are less than 35 % of half SRA,.

5.7 Erasure

After erasure, any signal amplitude shall be less than 5 % of the SRA=

5.6 Recording offset angle

On any track the angle that a flux transition across the track makes with a line perpendicular to Reference Plane B shall not exceed 9 minutes of arc.

6 Track format

The layout and positioning of tracks shalt be as specified in IS0 806311.

6.1 Use of tracks

Each track shall be a data track and shall be written serially in the direction from the BOT marker to the EOT marker. No data

for interchange shall be written between the BOT marker and the LP marker. Data for interchange shall be written after seni ing the LP marker and may continue to be mitten after sensing the EW marker.

6.2 Location of characters on the tracks

Each character shall be located in a byte of eight bit positions along the track numbered from 1 to 8 in order of recording.

6.3 Sequence of recording

The least-significant bit shall be record&d first. The information to ba interchanged shall be recorded serially by bit and by character.

Bit-positions: ..A321 187884321 18788432...

Forward tape motion :

Resuithg recording direction:

6.4 Data block

‘A data Mock shall consist of a preamble, a data portion, a CRC character and a postamble (see figure 61.

IS 12223 (Part 2) : 1989 IS0 8063/2 : 1986

PREAMBLE DATA CRC POSTAMBLE .

@IO.. 001 8-bit bytes

one 16 bit

byte

39 ZEROS minimum 12 bytes minimum 39 ZEROS minimum

47 ZEROS maximum 8 196 bytes maximum 47 ZEROS maximum

Figure 6

6.4.1 Preamble 6.5 Control block

The preamble, consisting of not less than 39 ZEROS Land not more than 47 ZEROS followed by a single ONE, shall be written

’

A control block shall consist of a preamble, two bytes of eight

ZEROS, and a postamble.

immediately preceding data in each data block.

6.4.2 Data portion

The data portion of a data block shall contain a minimum of 12 data bytes and a maximum of 8 192 data bvtes.

6.6 Gaps

6.6.1 Integrity of gaps

The gaps shall be erased.

6.4.3 Cyclic Redundancy Check (CRC) 6.6.2 Initial gap

The f6 bits following the data portion of a data block shall be a Cyclic Redundancy Check (CRC) character. This l&bit character shall be written in each data block following the data portion and immediately preceding the postamble, the least significant bit being recorded first. The polynomial generating the CRC shall be

l-16 + x15 + x2 + 1

The gap between the LP marker and the first data block shall be 152.4 mm min. 16 in min.) and 1.2 m max. (48 in max.).

6.6.3 Interblock gaps

The interblock gap shall have a minimum length of 31 mm (1.22 in) and a maximum length of 1.2 m 146 in). Any gap in excess of 1.2 m (46 in) shall be considered as the end of data on this track.

6.4.4 Poetemble

The postemble, consisting of a ONE followed by not less than 39 ZEROs and not more than 47 ZEROS. shall be written immediately following the CRC in each data L’. ok.

NOTE - The ability to start or stop within a gap of a given length is dependent on the tape speed selected from the range specified in IS0 8663/l sub-clause 7.5 and the acceleration and deceleration also specified in IS0 8%3/l sub-clause 7.7.

\

Bareno 01 Indian Standards .

BIS is a statutory institution established under the Bureau of Indian Standarde Act, 2986 to promote harmonious development of the atiivities of standardization, marking and quality certification of goods and attending to connected ahatters in the country.

Copyright

BIS has the copyright of all its publications. No part of these publications may be reproduced in any form without the prior permission in writing of BIS. This does not preclude the free use, in the course of implementing the standard, of necessary details, such as symbols and sizes, type or grade des,ignations. Enquiries relating to copyright be addressed to the Director ( Publications ), BIS.

Revision of Indian Standards

Indian Standards are reviewed periodically and revised, when nece’ssary and amendments, if any, are issued from time 10 time. Users of Indian Standards should ascertain that they are in possession of the latest amendments or edition. Comments on this Indian Standard may be sent to BIS giving the following reference :

Dot. Na. LTD 24 (1308)

Amendments Issoed Since Poblication

Amend No. Date of Issue Text Affected

Headquarters :

BUREAU OF INDIAN STANDARDS

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Telegrams :]Manaksanstha ( Common to all Of&es )

Telephone

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