ISO/IEC 10777:1991

I NTER NATIONAL ISO/IEC
STANDARD I0777
First edition
1991 -09-1 5
Information technology - 3,81 mm wide
magnetic tape cartridge for information
interchange - Helical scan recording -
DDS format
Technologies de l'information - Cartouche de bande magnétique de 3,81 mm de
large pour l'échange d'information - Enregistrement par balayage en spirale -
Format DDS
Reference number
ISO/IEC 10777 : 1991 (E)
ISOiIEC 10777:1991 (E)
Contents
Page
Section 1 - General
1 Scope
2 Conformance
2.1 Magnetic tape cartridge
2.2 Generating system
2.3 Receiving system
3 Normative references
4 Definitions
4.1 Absolute Frame Number (AFN)
4.2 automatic track finding (ATF)
4.3 Area ID
4.4 Average Signal Amplitude
4.5 azimuth
4.6 back surface
byte
4.7
cartridge
4.8
4.9 Channel bit
4.10 Data Format ID
4.1 1 Early Warning Point (EWP)
4.12 End of Data (EOD)
4.13 Error Correcting Code (ECC)
4.14 flux transition position
4.15 flux transition spacing
frame
4.16
4.17 housekeeping frame
4.18 Logical Beginning of Tape (LBOT)
4.19 magnetic tape
Master Standard Amplitude Calibration Tape
4.20
O ISO/IEC 1991
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or
utilized in any form or by any means, electronic or mechanical, including photocopying and
microfilm, without permission in writing from the publisher.
ISO/IEC Copyright Office 0 Case postale 56 0 CH-I211 Genève 20 0 Switzerland
Printed in Switzerland
ii
4.21 3
Master Standard Reference Tape
4.22 Optimum Recording Field
Partition boundary
4.23
4.24 Physical Beginning of Tape (PBOT)
4.25 Physical End of Tape (PEOT)
4.26 physical recording density
4.27 pre-recording condition
4.28 record
4.29 Reference Recording Field
Secondary Standard Amplitude Calibration Tape
4.30
Secondary Standard Reference Tape
4.31
4.32 separator
4.33 Standard Reference Amplitude
4.34 Tape Reference Edge
4.35 Test Recording Current
4.36 track
4.37 Virtual End of Tape (VEOT)
5 Environment and safety
5.1 Testing environment
5.2 Operating environment
5.3 Storage environment
5.4 Transportation
5.5 Safety
5.6 Flammability
Section 2 - Requirements for the case
of the case
6 Dimensional and mechanical characteristics
General
6.1
6.2 Overall dimensions (figures 6 and 7)
6.3 Loading grip (figure 6)
6.4 Holding areas (figure 6)
6.5 Notches of the lid (figures 5 and 8)
Lid dimensions (figures 6 to 8)
6.6
6.7 Optical detection of the Beginning and End of Tape (figures 9 and 12)
6.8 Bottom side (figures 10 and 11)
Locking mechanism of the slider
6.8.1
Access holes
6.8.2
Recognition, Sub-datums, and Write-inhibit Holes
6.8.3
Datum Holes
6.8.4
6.8.5 Access room for tape guides
6.8.6 Holes for accessing the hubs
internal structure of the lower half (figure 12)
6.8.7
Light path (figure 12)
6.8.8
Support Areas (figure 13)
6.8.9
Datum Areas (figure 13)
6.8.1 O
ISOhEC 10777:1991 (E)
Relationship between Support and Datum 4reas and Reference
6.8.1 1
Plane 2 (figure 14)
6.9 Hubs (figures 15, 16)
6.10 Leader and trailer attachment
6.1 1 lnterface between the hubs and the drive spindles (figure 17)
6.12 Opening of the lid (figure 18)
6.13 Release of the hub locking mechanism (figures 19, 20)
6.14 Label areas (figure 21, 22)
Section 3 - Requirements for the unrecorded tape
7 Mechanical, physical and dimensional characteristics of the tape
7.1 Materials
7.2 Tape length
7.2.1 Length of magnetic tape
7.2.2 Length of leader and trailer tapes
Tape width
7.3
Discontinuities
7.4
7.5 Total thickness
7.6 Longitudinal curvature
7.7 Cupping
7.8 Coating adhesion
7.9 Layer-to-layer adhesion
7.10 Tensile strength
7.10.1 Breaking strength
7.10.2 Yield strength
7.1 1 Residual elongation
7.12 Electrical resistance of coated surfaces
Light transmittance of the tape
7.13
8 Magnetic recording characteristics
8.1 Optimum Recording Field
8.2 Signai amplitude
8.3 Resolution
8.4 Overwrite
8.4.1 Physical recording densities of 750,6 ftpmm and 3002 ftpmm
8.4.2 Physical recording densities of 83,4 ftpmm and 1001 ftpmm
8.5 Ease of erasure
8.6 Tape quality
8.6.1 Missing pulses
8.6.2 Missing pulse zone
8.7 Signal-to-noise ratio (S/N) characteristic
iv
ISODEC 10777:1991 (E)
iection 4 - Requirements for an interchanged tape
Format
9.1 General
9.2 Basic Groups
9.2.1 Group Information Table
9.2.2 Block Access Table
9.3 Sub-Groups
9.3.1 G1 Sub-Group
9.3.2 G2 Sub-Group - Randomizing
9.3.3 G3 Sub-Group
9.3.4 G4 Sub-Group
9.3.5 Main Data Block
9.4 Sub Data Area
Pack Item No. 1
9.4.1
9.4.2 Pack Item No. 2
9.4.3 Pack Item No. 3
9.4.4 Pack Itdm No. 4
9.4.5 Pack item No. 5
No. 6
9.4.6 Pack Item
Pack Item No. 7
9.4.7
Pack Item No. 8
9.4.8
9.4.9 Sub Data Block
Method of recording
10.1 Physical recording density
Long-term average bit cell length
10.2
Short-term average bit cell length
10.3
10.4 Rate of change
10.5 Bit shift
10.6 Read signal amplitude
10.7 Maximum recorded levels
Track geometry
11.1 Track configuration
11.2 Average track pitch
Variations of the track pitch
11.3
11.4 Track width
Track angle
11.5
Track edge linearity
11.6
Track length
11.7
11.8 Ideal tape centreline
11.9 Azimuth angles
Recording of blocks on the tape
12.1 Recorded Main Data Block
ISODEC 10777:1991 (E)
12.2 Recorded Sub Data Block
Margin Blocks, Preamble Blocks and Postamble Blocks
12.3
12.4 Spacer Blocks
Format of a track
13.1 Track capacity
13.2 Positioning accuracy
13.3 Tracking scheme
14 Layout of a Single Data Space tape
14.1 Device Area
14.2 Reference Area
Position Tolerance Band No. 1
14.3
14.4 System Area
14.4.1 System Preamble
14.4.2 System Log
68 c
14.4.3 System Postamble
Position Tolerance Band No. 2
14.4.4
14.4.5 Vendor Group Preamble
14.5 Data Area
14.5.1 Vendor Group
14.5.2 Recorded Data Group
14.5.3 ECC3
14.5.4 Multiple recorded instances
14.5.5 Repeated frames
14.5.6 Appending and overwriting
14.6 EOD Area
14.7 Post-EOD Area
Early Warning Point - EWP
14.8
14.9 Initialization
15 Layout of a Partitioned tape
73 0
15.1 Overall magnetic tape layout
15.1.1 Device Area
15.1.2 Partition 1
15.1.3 Partition O
15.2 Area ID
System Area Pack Items No. 3 and No. 4 76
15.3
15.4 Empty Partition
15.5 Initialization of Partitioned Tapes
16 Housekeeping frames
16.1 Amble Frames 77
16.2 System Log Frames 77
16.3 Tape Management Frames
vi
Annexes
Annex A - Measurement of the light transmittance of the prisms 79
Annex B - Recognition Holes
Annex C - Means to open the lid 82
Annex D - Measurement of light transmittance of tape and leaders
Annex E - Measurement of Signal-to-Noise Ratio
Annex F - Method for determining the nominal and the maximum allowable
recorded levels
Annex G - Representation of 8-bit bytes by 10-bit patterns
Annex H - Measurement of bit shift
Annex J - Recommendations for transportation
Annex K - Method of measuring track edge linearity
Annex L - Read-After-Write
1 O0
Annex M - Example of the content of a Basic Group No. O

Foreword
I
IS0 (the International Organization for Standardization) and IEC (the International
Electrotechnical Commission) form the specialized system for worldwide standardiz-
ation. National bodies that are members of IS0 or IEC participate in the development
of International Standards through technical committees established by the respective
organization to deal with particular fields of technical activity. IS0 and IEC technical
committees collaborate in fields of mutual interest. Other international organizations,
governmental and non-governmental, in liaison with IS0 and IEC, also take part in the
work.
In the field of information technology, IS0 and IEC have established a joint technical
committee, ISOAEC JTC 1. Draft International Standards adopted by the joint
technical committee are circulated to national bodies for voting. Publication as an
International Standard requires approval by at least 75 070 of the national bodies casting
a vote.
International Standard ISOAEC 10777 was prepared by the European Computer
Manufacturers Association (as Standard ECMA-139) and was adopted, under a special
“fast-track procedure”, by Joint Technical Committee ISO/IEC JTC 1, Information
technology, in parallel with its approval by national bodies of IS0 and IEC.
Annexes A, D to H and K form an integral part of this International Standard.
Annexes B, C, J, L and M are for information only.
Patents
During the preparation of the ECMA standard, information was gathered on patents
upon which application of the standard might depend. Relevant patents were identified
as belonging to Hewlett Packard Limited and the Sony Corporation. However, neither
ECMA, nor ISOAEC can give authoritative or comprehensive information about
evidence, validity or scope of patent and like rights. The patent holders have stated that
licences will be granted under reasonable and non-discriminatory terms. Communi-
cations on this subject should be addessed to
Hewlett Packard Limited
Computer Peripherals Bristol
Filton road
Stoke Gifford
Bristol BS12 642
United Kingdom
Sony Corporation
Licensing and Trademark Division
6-7-35 Kitashinagawa
Shinagawa-ku
Tokyo 141
Japan
Introduction
This International Standard specifies the characteristics of a 3,81 mm wide magnetic tape
cartridge to enable interchangeability of such cartridges. The format used is known as
Digital Data Storage (DDS).
3 Normative references
The following standards contain provisions which, through reference in this text, constitute
provisions of this international Standard. At the time of publication, the editions indicated were
valid. All standards are subject to revision, and parties to agreements based on this International
Standard are encouraged to investigate the possibility of applying the most recent editions of the
standards indicated below. Members of IEC and IS0 maintain registers of currently valid
International Standards.
IS0 W527: 1966, Plastics - Deternlination of tensile properties.
IS0 1302: 1978, Technical Drawings - Method of indicating Surface Texture on Drawings.
IEC 950: 1988, Safety of lnformarion Technology Equipment (ITE).
4 Definitions
For the purpose of this International Standard, the following definitions apply.
Absolute Frame Number (AFN) : A sequence number, encoded in the frame.
4.1
automatic track finding (ATF) : The method by which tracking is achieved.
4.2
4.3 Area ID : An identifier defining the area of the tape and specifying the types of frame written.
4.4 Average Signal Amplitude : The average peak-to-peak value of the output signal from the read
head at the fundamental frequency of the specified physical recording density over a minimum of
7,s mm of track, exclusive of missing pulses.
azimuth : The angular deviation, in degrees, minutes and seconds of arc, made by the mean flux
4.5
transition line with the line normal to the centreline of the recorded track.
4.6 back surface : The surface of the tape opposite to the magnetic coating which is used to record
data.
4.7 byte : An ordered set of bits acted upon as a unit.
4.8 cartridge : A case containing magnetic tape stored on twin hubs.
4.9 Channel bit : A bit after 8-10 transformation.
4.10
Data Format ID : An identifier specifying which data format is being used on the tape.
4.11 Early Warning Point (EWP) : A point along the length of the tape at which warning is given of the
approach, in the forward direction of tape motion, of the partition boundary or of the Physical End
of Tape.
4.12 End of Data (EOD) : The point on the tape at the end of the group which contains the last user
data.
4.13 Error Correcting Code (ECC) : A mathematical algorithm yielding check bytes used for the
detection and correction of errors.
4.14 flux transition position : That point which exhibits maximum free-space flux density normal to the
tape surface.
4.15 flux transition spacing : The distance along a track between successive flux transitions.
4.16 frame : A pair of adjacent tracks with azimuths of opposite polarity, in which the track with the
positive azimuth precedes that with the negative azimuth.
4.17
Housekeeping Frame : A frame which contains no user data and which is identified as such by the
values in the data fields therein.
1.18 Logical Beginning of Tape (LBOT) : The point along the length of the tape where a recording of
data for interchange commences.
1.19 magnetic tape : A tape which will accept and retain the magnetic signals intended for input, output
and storage purposes on computers and associated equipment.
1.20 Master Standard Amplitude Calibration Tape : A pre-recorded tape on which the standard signal
amplitudes have been recorded in the tracks of positive azimuth, 23,O pm wide, at nominal track
pitch, on an AC-erased tape.
NOTE 1 - The tape includes recording made at X3,4 ftpmm, 333,h ftpmm, 500,4 ftpmm, IOOI ftpmm and 1501 ftprnm.
NOTE 2 - The Master Standard Amplitude Calibration Tape has been established by Sony Corporation.
i.21 Master Standard Reference Tape : A tape selected as the standard for Reference Recording Field,
Signal Amplitude, Resolution, Overwrite and Signal-to-Noise Ratio.
NOTE 3 - The Master Standard Reference Tape has been established by Sony Corporation.
1.22 Optimum Recording Field : in the plot of Average Signal Amplitude against the recording field at
the physical recording density of 3002 ftpmm, the field that causes the maximum Average Signal
Amplitude.
1.23 Partition boundary : The point along the length of a magnetic tape at which Partition 1 ends and
Partition O commences.
1.24 Physical Beginning of Tape (PBOT) : The point where the leader tape is joined to the magnetic
tape.
: The point where the trailer tape is joined to the magnetic tape.
1.25 Physical End of Tape (PEOT)
1.26 physical recording density : The number of recorded flux transitions per unit length of track,
expressed in flux transitions per millimetre (ftpmm).
1.27 pre-recording condition : The recording levels above which a tape intended for interchange shall
not previously have been recorded.
1.28 record : Related data treated as a unit of information.
Reference Recording Field : The Optimum Recording Field of the Master Standard Reference
1.29
Tape.
1.30 Secondary Standard Amplitude Calibration Tape : A tape pre-recorded as defined for the Master
Standard Amplitude Calibration Tape; the outputs are known and stated in relation to those of the
Master Standard Amplitude Calibration Tape.
NOTE 4 - Secondary Standard Amplitude Calibration Tapes can be ordered from Sony Corporation, Audio Device
Business Department, Component Marheting Group, 4-10-18, Takanawa, Minato-ku, Tokyo 108, Japan, under Part
Number TY-700OG until the year 2001). It is intended that these be used for calibrating tertiary reference tapes for use in
routine calibration.
1.31 Secondary Standard Reference Tape : A tape the performance of which is known and stated in
relation to that of the Master Standard Reference Tape.
NOTE 5 - Secondary Standard Reference Tapes can be ordered from Sony Corporation, Major Customer Division,
Magnetic Products Group, 6-7-35, Kitashinagawa, Shinagawa-ku, Tokyo 141, Japan, under Part Number RSD 1079 until
the year 2000. It is intended that these be u5ed for calibrating tertiary reference tapes for use in routine calibration.
1.32 Separator : A record containing no user data, which is used to separate data.
4.33 Standard Reference Amplitude : The Average Signal Amplitude from the tracks of positive
azimuth of the Master Standard Amplitude Calibration Tape at a specified physical recording
density.
4.34 Tape Reference Edge : The bottom edge of the tape when viewing the recording side of the tape,
with the PEOT to the observer's right.
4.35 Test Recording Current : The current that produces the Reference Recording Field.
4.36 track : A diagonally positioned area on the tape along which a series of magnetic signals may be
recorded.
4.37 Virtual End of Tape (VEOT) : The point along the length of the magnetic tape within Partition 1
which defines the end of the part of Partition 1 which is usable for recording data for interchange.
5 Environment and safety
Unless otherwise stated, the conditions specified below refer to the ambient conditions of the air
immediately surrounding the cartridge.
5.1 Testing environment
Unless otherwise stated tests and measurements made on the tape cartridge to check the
requirements of this international Standard shall be carried out under the following conditions:
: 23 "C $: 2 "C
Temperature
Relative Humidity : 40 70 to 60 %
Conditioning period
before testing : 24 hours
5.2 Operating environment
Cartridges used for data interchange shall be capable of operating under the following
conditions:
: 5 "C to 45 "C
Temperature
: 20 5% to 80 %
Relative Humidity
Wet Bulb Temperature : 26 "C max.
There shall be no deposit of moisture on or in the cartridge.
Conditioning before operating:
If a cartridge has been exposed during storage and/or transportation to a condition outside the
above values, before use the cartridge shall be conditioned in the operating environment for a
time at least equal to the period during which it has been out of the operating environment, up
to a maximum of 24 hours.
NOTE h - Rapid variations of temperature should be avoided.
5.3 Storage environment
For long-term or archival storage of cartridges the following conditions shall be observed:
: 5 "C to 32 "C
Temperature
: 20 % to 60 96
Relative Humidity
: 26 "C max.
Wet Bulb Temperature
The stray magnetic field at any point on the tape shall not exceed 4000 Nm. There shall be no
deposit of moisture on or in the cartridge.
5.4 Transportation
Recommended limits for the environment to which a cartridge may be subjected during trans-
portation, and the precautions to be taken to minimize the possibility of damage, are provided in
annex J.
5.5 Safety
The cartridge and its components shall satisfy the requirements of IEC 950.
5.6 Flammability
The cartridge and its components shall be made from materials, which if ignited from a match
flame, do not continue to burn in a still carbon dioxide atmosphere.
Section 2 - Requirements for the case
6 Dimensional and mechanical characteristics of the case
6.1 General
The case of the cartridge shall comprise:
- an upper half,
- a lower half,
-
a slider movably mounted on the lower half,
-
a lid pivotally mounted on the upper half.
In the drawings, using third angle projection, an embodiment of the cartridge is shown as an
example.
Figure 1 is a perspective view of the cartridge seen from top.
Figure 2 is a perspective view of the cartridge seen from bottom.
Figure 3 is a partial view of the rear side.
Figure 4 is a schematic view showing the Reference Planes X, Y and 2.
Figure 5 shows the front side.
Figure 6 shows the top side with the lid in closed position.
Figure 7 shows the left side.
Figure 8 shows the top side with the lid in open position.
Figure 9 shows the left side with the lid in open position.
Figure 10 shows the bottom side with the lid and the slider in closed position.
Figure 11 shows the bottom side with the lid and the slider in open position.
Figure 12 is a view from the top of the inside of the lower half with the upper half
removed.
Figure 13 is a view of the bottom half with the lid and the slider in open position.
Figure 14
is a view of the left side with the lid and the slider in open position.
Figure 15 is a top view of a hub.
ISOflEC 10777:1991 (E)
Figure 16 is a side view of a hub with partial cross-section.
Figure 17 is a partial cross-section through a hub and both halves of the case showing the
interface with the drive spindle.
Figure 18 shows at a larger scale the lid in the open position.
Figure 19, 20 show at a larger scale the functional relationship between the lid and the locking
mechanism of the hubs.
Figure 21, 22 show the label areas on the top and the rear side.
The dimensions are referred to three orthogonal Reference Planes X, Y and Z (figure 4).
6.2 Overall dimensions (figures 6 and 7)
The overall dimensions of the case with the lid in the closed position shall be:
LI = 73,O mm f 0,3 mm
L2 = 54,O mm f 0,3 mm
L3 = 10,5 mm f 0,2 mm
The edges formed by the rear side and the left and right sides shall be rounded off with a radius
RI = 1,5 mm max.
The two edges of the lid shall be rounded off with a radius
R2 = 0,5 mm max.
6.3 Loading grip (figure 6)
The top side shall have a loading grip for loading and positioning the cartridge into the drive.
The position and dimensions of the loading grip shall be
L4 = 25,5 mm f 0,3 mm
Lg = 10mm min.
L6 = 5,O mm f 0,2 mm
L7 = 2,O mm min.
The depth of the loading grip below the surface of the top side shall be
+ 0,2 mm
0~ mm - O,O mm
6.4 Holding areas (figure 6)
The two areas shown shaded in figure 6 shall be the areas along which the cartridge shall be held
down when inserted in the drive. Their positions and dimensions shall be
Le = 6,O mm f 0,l mm
L9 = 5,O mm f 0,l mm
6.5 Notches of the lid (figures 5 and 8)
The lid shall have two pairs of notches.
The first pair of notches, the slider lock release notches, allows elements of the drive to release
the locking mechanism of the slider. The positions and dimensions of these notches shall be

ISOOEC 10777:1991 (E)
Llo = 0,4 mm max.
L11 = 3,O mm min.
L12 = 1,2 mm f 0,l mm
Li3 = 49,8 mm f 0,2 mm
The second pair of notches, the slider movement notches, allows elements of the drive to move
the slider from the closed to the open position (see also 6.8.1). The positions and dimensions of
these notches shall be
Li1 = 3,0 mm min.
Li4 = 0,9 mm min.
Li5 = 73 mm le 0,l mm
Llh = 36,OO mm I 0,15 mm
6.6 Lid dimensions (figures 6 to 8)
The lid is shown in the closed position in figure 6 and 7. Its dimensions shall be
Li7 = 1,2 mm _+ O,] mm
Llg = 6,8 mm f 0,4 mm
Li9 = 1,l mm f 0,l mm
L20 = 2,O mm I 0,l mm
L~I = 6,4 mm f 0,2 mm
L22 = 1,5 mm f 0,l mm
R3 = 6,8 mm le 0,4 mm
The lid shall have a chamfer of 45" by
L23 = 1,5 mm f 0,l mm
-24 shown in figure 7, which
There shall be a dimensional relationship between the height
includes the slider and the upper half, and the height L25 of the lid. When a vertical force of 1 N
is exerted on the upper half the following condition shall be met.
L24 = 10,5 mm I 0,2 mm
L25 5 L24
When no force is exerted
L24 = 10,9 mm max.
In figure 8 the lid is shown in the open position. The distance from the front edge of the lid to
the rear side shall be
L26 = 55,s mm le 0,3 mm.
Optical detection of the Beginning and End of Tape (figures 9 and 12)
6.7
Means for the optical detection of the beginning and end of tape shall be provided. These shall
consist of a pair of windows on the left and right sides of the case (see also figure 18). The
design of these windows allows this detection for two different drive designs:
- either a light source and a detector are provided in the drive on each side of the cartridge, in
which case the light enters the case through the upper windows, falls on a prism (see section
ISODEC 10777:1991 (E)
A-A) mounted inside the case, which reflects this light so that it goes through the tape and
falls on the detector through the lower window; the light transmittance of the prism shall be
greater than 50% of that of a reference prism when measured as specified in annex A,
-
or, the light of a light source within the drive passes through the tape from inside the
cartridge and falls through the lower windows onto the detectors placed on each side of the
case.
The positions and dimensions of these windows allow the cartridge to be used with drives imple-
menting either system, they shall be
L27 = 6.20 mm f 0,lO mm
L2x = 7,65 mm f 0,lO mm
L30 = 3,9 mm t 0,l mm
L31 = 1,8 mm f 0,l mm
L32 = 7,O mm f 0,2 mm
L33 = 2,5 mm min.
Dimension L32 specifies the position of the rear eLge of the windows relative to Reference Plane
Y. Dimension L33 shall be measured relative to this rear edge.
10 and 11)
6.8 Bottom side (figures
The bottom side is shown in figure 10 with the lid and the slider in the closed position and in
figure 11 with both in the open position.
The dimension L34 of the bottom half, L35 of the slider and L36 of the lid shall satisfy the
following conditions
L34 = 73,O mm f 0,3 mm
L35 5 L34
L36 L34
Locking mechanism of the slider
6.8.1
The cartridge shall have a locking mechanism for the slider which locks it in the closed and
open positions. The design of this mechanism is not specified by this International Standard,
except for the different forces acting on the slider, and for its detent.
The slider shall be spring-loaded by a spring holding it in the closed position when it is
unlocked. The force required to operate the slider shall not exceed 2 N.
The slider shall have two grooves with an opening at each end. The detent of the locking
mechanism shall protrude through these openings so as to hold the slider in both open and
closed positions. The detent shown in cross-section C-C is only an example of implementation.
The grooves are parallel to Reference Plane 2 and aligned with the slider lock release notches
of the lid. The positions and dimensions of the grooves and of the openings for the detent of
the locking mechanism when the slider is in the closed position shall be
L37 = 1,2 mm t 0,l mm
L38 = 49,8 mm I 0,2 mm
ISODEC 10777:1991 (E)
L39 = 10,O mm I 0,l mm
+ 0,5 mm
L40 = 290 mm - 0,o mm
L4l = 3,O mm min.
L42 = 1,5 mm min.
L43 = 0,8 mm f 0,l mm
X = 450 min.
L45 = 0,65 mm I 0,05 mm
The position and dimensions of the openings for the detent when the slider is held in the open
position are determined by L39, L40, L43 and L44.
In the closed position of the slider, the maximum force to be exerted on the detent in a direc-
Z and over a stroke of 0,65 mm shall be 0,5 N max.
tion perpendicular to Reference Plane
In the open position of the slider the holding force shall be 0,3 N min.
6.8.2 Access holes
The slider shall have two circular access holes (see section B-B) which, in the open position of
the slider, allow penetration of the drive spindles into the hubs. The diameters of these access
holes shall be
dl = 10,O mm f 0,2 mm
d2 = 12,O mm max.
Recognition, Sub-datums, and Write-inhibit Holes
6.8.3
The bottom half shall have a number of holes on an edge at its rear. This edge shall be
defined by
L4 = 45,2 mm f 0,2 mm
L47 = 49,2 mm I 0,2 mm
The centres of these holes lie on a line perpendicular to Reference Plane Y at a distance from
Reference Plane X of
L48 = 47,2 mm t 0,2 mm
6.8.3.1 Recognition Holes
There shall be four Recognition Holes numbered from 1 to 4 as shown in figure 10. Their
positions and dimensions shall be
d3 = 2,5 mm f 0,l mm
L49 = 1,0 mm f 0,l mm
,550 = 56,O mm f 0,3 mm
L51 = 4,O mm t 0,l mm
ISODEC 10777:1991 (E)
L52 = 1,0 mm f O,] mm
L53 = 3,O mm min.
All Recognition Holes shall have the cross-section shown in cross-section F-F in figure 11
for Recognition Hole No. 1.
One of the two cross-sections F-F shows a Recognition Hole closed by means of a plug, the
other shows it with the plug punched out. These plugs shall withstand an applied force of
0,5 N max. without being punched out.
This International Standard prescribes the following states of these holes:
Recognition Holes No. 1 to No. 3 shall be closed
Recognition Hole No. 4 may be open or closed
of the states of the Recognition Holes No. 1, No. 2 and No. 3 are
Other combinations
reserved for future applications (see annex B).
6.8.3.2 Write-inhibit Hole
The position and dimensions of the Write-inhibit Hole shall be
d4 = 2,5 mm 1: O,] mm
L50 = 56,O mm k 0,3 mm
is open, recording on the tape is inhibited, when it is closed
When the Write-inhibit Hole
recording is enabled.
The Write-inhibit Hole shall have the cross-section shown in cross-section F-F in figure 11
for Recognition Hole No. 1. One of the two cross-sections F-F shows the hole closed by
means of a plug, the other shows it with the hole punched out. These plugs shall withstand
an applied force of 0,5 N max without being punched out.
The case may have a movable element allowing the Write-inhibit Hole to be opened and
If present, this element shall be such that the state of Write-inhibit Hole is visible
closed.
(see figure 3 as an example). Such an element shall neither be broken nor moved by a force
smaller than 0,5 N.
Regardless of whether a plug or a movable element is used to select the open and closed
states of the Write-inhibit Hole, the following dimensions from cross-section F-F shall
define the closed and open states, respectively.
L52 = 1,0 mm f 0,l mm
L53 = 3,O mm min.
6.8.3.3 Sub-datum Holes
These holes are used to position the cartridge in the drive. Their position and dimensions
shall be as follows.
- The hole seen below the Write-inhibit Hole in figure 11 shall have an elongated form
and the same cross-section E-E as shown for the other hole.
L54 = 45.5 mm 1: 0,2 mm
+ 0,l mm
45 = 395 mm - 0,o mm
ISODEC 10777:1991 (E)
- The position and dimensions of the other Sub-datum Hole shall be
06 = 1,0 mm min.
L57 = 53 mm f 0,l mm
L58 = 2,O mm min.
L59 = 1,2 mm min.
The edge of both Sub-datum Holes shall have a chamfer of
0,2 mm f 0,l mm.
Datum Holes
6.8.4
The lower half has two Datum Holes also used to position the cartridge within the drive. One
of them has an elongated form, the other is circular. Cross-section D-D shown for the latter
also applies to the former. Their positions and dimensions shall be
LH) = 51,O mm f 0,l mm
L63 = 3,O mm min.
+ 0,05 mm
= 2780 mm - O,OO mm
d7
The upper edge of both Datum Holes shall have a chamfer of 0,2 mm k 0,l mm.
6.8.5 Access room for tape guides
When the cartridge is inserted into the drive, tape guides in the drive pull out the tape toward
the heads of the drive. The shape and dimensions of the access room provided by the cartridge
for these tape guides shall be (see also 6.8.7.5):
LM = 3,1 mm max.
L65 = 5,6 mm min.
LM = 11,O mm max.
L68 = 6,7 mm min.
CL = 45" f 1"
L69 = 47,9 mm min.
+ 0,OO mm
L70 = 3,3Omm - 0,15 mm
Holes for accessing the hubs
6.8.6
The lower half has two holes through which the spindles of the drive can access the hubs
when the slider is in the open position. The positions and dimensions of these holes shall be
d8 = 9,O mm t 0,l mm
L71 = 29,OO mm f 0,15 mm
L72 = 10,5 mm t 0,l mm
L73 = 30,O mm t 0,l mm
6.8.7 Internal structure of the lower half (figure 12)
In figure 12 the different elements of the inside of the lower half are shown. There shall be a
locking mechanism for the hubs to prevent them from rotating when the lid is in the closed
position. The design of this locking mechanism is not specified by this International Standard,
thus it is not shown in figure 12. Locking and unlocking of the hubs shall depend upon the
position of the lid as specified in 6.13.
6.8.7.1 Diameter of the wound tape
The diameter of the tape wound on a hub shall be
dy = 36,5 mm max.
6.8.7.2 Tape wind
The magnetic surface of the tape shall face outwards.
6.8.7.3 Tape motion
The forward direction of tape motion is from the left side of the cartridge to its right side
(see figure 1 and 2).
6.8.7.4 Guide posts
The tape shall pass around two guide posts in the cartridge, the axes of which are perpen-
dicular to Reference Plane Z and pass through the centres of the Datum Holes. The posi-
tions and dimensions of these guide posts shall be:
- their positions are determined by those of the centres of the Datum Holes,
- their cross-section shall be circular with a radius
R4 = 3,O mm t 0,l mm
over an angle of 180" in clockwise sense starting at angle
P = 45" t 1"
-
their cross-section over the other half of 180” is not specified by this International
Standard.
6.8.7.5
Position of the tape in the case (view A)
When the tape runs from one guide post to the other it shall remain between two planes
parallel to Reference Plane Z. The distance of these planes to Reference Plane Z shall be
L74 = 1,4 mm min.
L75 = 6,4 mm max.
The design centre for the position of the tape centreline is
L7h = $9 mm
The height of the access room specified in 6.8.5 for the tape guides shall be
+ 0,6 mm
L77 = 890 mm - 0,o mm
6.8.7.6 Tape path zone
When the cartridge is inserted into the drive, the tape is pulled outside the case by tape
guides as mentioned above. It is then no longer in contact with the guide posts. The tape
path zone of the case is the zone in which the tape must be able to move freely. This zone
is defined by
L78 = 53 mm ir 0,l mm
L79 = 56,5 mm ir 0,3 mm
Lxo = 8,O mm I 0,2 mm
6.8.8 Light path (figure 12)
As specified in 6.7 there is a lower window in the right and left sides of the case through
which light having passed through the tape can pass and fall onto a detector of the drive. In
order to ensure that the corresponding light path is not obstructed by inner elements of the
case, its configuration in this zone shall be as follows.
The position and dimensions of the lower window are specified by L30 and L~I (see figure 9).
The dimensions
Lx1 = 1,5 mm max.
L82 = 5,O mm min.
ensure that no elements of the case obstruct the light path.
6.8.9 Support Areas (figure 13)
When the cartridge is inserted into the drive and held in position by forces perpendicular to
Reference Plane Z acting on the Holding Areas (see 6.4), it shall be supported by three
Supporting Areas A’, B’, C’ on its bottom side, shown shaded in figure 13. The position and
dimensions of these areas shall be as follows.
- Areas A’ and B’ are not specified by this International Standard because they depend on
parts of the lower half for which this lnternational Standard does not specify requirements.
-
Area C’ shall be defined by
Lx3 = 1,0 mm k 0,l mm
ISOAEC 10777:1991 (E)
L84 = 49,O mm rt 0,3 mm
6.8.10 Datum Areas (figure 13)
There shall be two annular Datum Surfaces A and B and one circular such surface C. All
three Datum Areas shall lie in Reference Plane Z. Their position and dimensions shall be:
- Datum Area A shall be centred on the intersection of Reference Planes X, Y and 2, its
inner diameter shall be d7 (see 6.8.4 and figure 1 l), its outer diameter shall be
dlo = 5,O mm f 0,l mm
-
Datum Area B shall be centred on the intersection of Reference Planes X and Z at a
distance Lm (see 6.8.4 and figure 11) from the centre of Datum Area A. Its inner
dimensions shall be L61 and L62, its outer diameter shall be dio.
-
Datum Area C shall be centred on a point defined by
L85 = 42'0 mm f 0,3 mm
LM = 25,5 mm f 0'3 mm
Its diameter shall be dlo.
6.8.11 Relationship between Support and Datum Areas and Reference Plane Z (figure 14)
Support Area A' shall be coplanar with Datum Area A within 0,l mm.
Support Area B' shall be coplanar with Datum Area B within 0,l mm.
Support Area C' shall be parallel to Reference Plane Z within 0,l mm. It shall be at a distance
L87 = 1,lO mm f 0,05 mm
from Reference Plane Z.
6.9 Hubs (figures 15,16)
The dimensions of the hubs shall be
+ 0,OS mm
dll = 6760 mm - O,OO mm
+ 0,O mm
di2 = 8,s mm - 0,1 mm
d13 - - 15,OO mm f 0,05 mm
fl = 60" rt 1"
Y = 45" i 1"
The two cylindrical surfaces with diameters dl1 and dl3 shall be Co-axial within 0,OS mm.

ISODEC 10777:1991 (E)
The torque necessary to rotate the hub with a partially or fully wound tape shall be 0,0002 N.m
max.
6.10 Leader and trailer attachment
The material of the leader and trailer and their attachment to the hubs and to the tape shall be
such that when subjected to a force of 5 N max. they will neither break nor be detached from the
hubs or the tape.
6.1 1 Interface between the hubs and the drive spindles (figure 17)
The interface between the hubs and the spindles, shown in figure 17 in cross-section, is specified
in terms of the following relationships:
1,2 mm max.
d15 - d14 = i,~ mm min.
Ly1 - Loo = 1,3 mm max.
NOTE 7 - It is expected that the top of the drive spindle will not penetrate within the hub beyond distance
Ld = 7,b5 mm max. above Reference Plane 2.
6.12 Opening of the lid (figure 18)
When the lid is opened its lower front edge moves along an arc of a circle with radius
R5 = 9,6 mm f 0,2 mm
The centre of rotation is defined by Li7 and L21. The end position of the lid, i.e. when it is fully
open, is defined by
Lo2 = 10,9 mm f 0,2 mm
Lo3 = 0,3 mm it 0,l mm
Lc)~ = 6,3 mm f 0,2 mm
The force F required to open the lid shall not exceed 1,2 N. It shall be applied at a distance
Lo5 = $0 mm f 0,l mm
measured parallel to Reference Plane 2 from the centre of rotation of radius R5 (see also annex
Cl.
6.13 Release of the hub locking mechanism (figures 19, 20)
As mentioned in 6.8.7 the design of the locking mechanism for the hubs is not specified by this
International Standard, except that it shall be connected to the lid so that the hubs are locked or
unlocked as a function of the angular position of the lid.
When the lid rotates from the closed to the open position (clockwise as seen in figure 19, 20) the
hubs shall remain locked as long as the lid has not reached the position defined by:
Ly6 = 7,O mm
L97 = 73 mm I 0,2 mm
as shown in figure 19.
The hubs shall be completely released as soon as the lid has reached the position defined by:
Lgs = 10,3 mm
L~pl = 6,6 mm f 0,2 mm
ISOAEC 10777:1991 (E)
as shown in figure 20.
6.14 Label areas (figure 21, 22)
On the top and rear sides of the case there shall be an area on which adhesive labels can be
placed. The dimensions of these areas shall be
Llm = 28,9 mm max.
L101 = 5,2 mm min.
L102 = 43,4 mm max.
Li03 = 39,4 mm max.
Li04 = 8,8 mm max.
Rg = 0,5 mm min.
ISODEC 10777:1991 (E)
QJ
V
vj
L.
m
rr)
U
Li
a
M
rs
Y\
rl
CI
U
U
I
I
M
M
.CI
cy
iz
ISOAEC 10777:1991 (E)
Li0
Lllj
Li:
j-
@ L6
I LIL
,151 j
Lll
t
I-- I
ii9
Figure 5 - Front side,
\t
/
lid closed
Ri
Figure 6 - Top side,
R2
lid closed
L3
Figure 7 - Left side, lid closed
I-’
ISOAEC 10777:1991 (E)
r
Pr Ism
-
--------
I*
FA L26
I-
I
Figure 8 - Top side,
A L28
lid open
L29
c
Sect ion AA
“‘i
II
L 2 91
Figure 9 - Left side, lid open
~
ISODEC 10777:1991 (E)
I
L38
V
t
di
t- El
d2
SECT I ON CC
SECT ON BB
Figure 10 - Bottom side, lid closed
.I
L70
L71 -
L c
\
I-
- 4
L56
__I - dû
L554
L60
L69
L57
Y
Il tl
.c
TL49tL5ll
P-
F' I
'd 7
L59
L53
, L63, L52 I
L58
SECT I ON FF SECT I ON FF
SECT I ON DD SECT I ON EE
(PUNCH OUT)
Figure 11 - Bottom side, lid open
$SO/IEC 10777:1991 (E)
TAPE PATH ZONE
R4
\
A
L79
R4 ’
/
TAPE PATH ZONE /
LIGHT PATH(PRISM)
LIGHT PATH(DIRECT1 /
“i-
L76 -1 ~ l
SECT I ON QQ
View A
L
Figure 12 - Inside view of the lower half

a
dl0
B
L84
g-
A' 'I
L85
Figure 13 - Bottom side, lid and slider in open position
L87 4
Figure 14 - Left side, lid open
ISOAEC 1077h1991 (E)
di
VIEW B
Figure 15 - Top view of a hub
I
I
L90 Id
I Laal-
I
J L
/
f /I
Figure 16 - Side view of a hub
L 91
Ld
T
U
Figure 17 - Interface with the drive spindle
ISODEC 10777:1991 (E)
Figure 18 - Lid in completely open position
L99
t
Figure 19 - Extreme position Figure 20 - Minimum position
of the lid for which of the lid for
the hubs are still which the hubs are
locked completely unlocked
I
I
Li02
I LI01
LI01 L
-
I
Figure 21 - Top side, label area
Li04
/
R6
R6
Figure 22 - Rear side, label area
'26
rtion 3 - Requirements for the unrecorded tape
Mechanical, physical and dimensional characteristics of the tape
Materials
The recordable area of the tape shall consist of a base material (oriented polyethylene tereph-
thalate or its equivalent) coated on one side with a strong yet flexible layer of ferromagnetic
material. The back surface may be coated.
The leader and trailer tapes shall consist of a translucent length of the same or equivalent base
material without the ferromagnetic coating or the back coating.
! Tape length
2.1 Length of magnetic tape
The length of tape between PBOT and PEOT shall be 3,O m minimum and 60,5 m maximum.
Length of leader and trailer tapes
2.2
The length of the leader and trailer tapes shall be 60 mm k 5 mm.
I Tape width
The width of the magnetic tape and of the leader and trailer tapes shall be
+ 0,OO mm
3981 mm - 0,02 mm
The width shall be measured across the tape from edge to edge when the tape is under a tension
of 0,18 N maximum.
I Discontinuities
Between PBOT and PEOT there shall be no discontinuities such as those produced by tape
splicing or perforations.
i Total thickness
The total thickness of the magnetic tape at any point shall be 13 pm f 1 pm.
Longitudinal curvature
The radius of curvature of the edge of the tape shall not be less than 33 m.
Procedure
Allow a 1 m length of tape to unroll and assume its natural curvature on a flat smooth surface.
Measure the deviation from a 1 m chord. The deviation shall not be greater than 3,s mm. This
deviation corresponds to the minimum radius of curvature of 33 m if measured over an arc of a
circle.
I
Cupping
The departure across the width of tape from a flat surface shall not exceed 0,5 mm.
Procedure
Cut a 1,0 m f 0,l m length of tape. Condition it for a minimum of 3 hours in the test environ-
ment by hanging it so that the coated surface is freely exposed to the test environment. From the
centre portion of the conditioned tape cut a test piece of 25 mm length. Stand the test piece on
its end in a cylinder which is at least 25 mm high with an inside diameter of 4,l mm k 0,2 mm.
With the cylinder standing on an optical comparator measure the cuppi
...