ISO 6902:1984
(Main)Information processing — Magnetic disk for data storage devices — 107 500 flux transitions per track, 266 mm (10.5 in) and 356 mm (14 in) diameter
Information processing — Magnetic disk for data storage devices — 107 500 flux transitions per track, 266 mm (10.5 in) and 356 mm (14 in) diameter
Describes the mechanical, physical and magnetic disks intended for mounting in data storage devices. Defines requirements for disks regarding satisfactory performance at 107 500 flux transitions per track. Distinguishes between disk types A na B in terms of their outer diameter and some numeric values.
Traitement de l'information — Disque magnétique pour unités de stockage des données — 107 500 transitions de flux par piste, diamètres 266 mm (10,5 in) et 356 mm (14 in)
General Information
Standards Content (Sample)
International Standard
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION.MEXfiYHAPOLJHAR OPrAHM3AUMfI I-IO CTAH~APTM3ALUIM~ORGANlSATlON INTERNATIONALE DE NORMALlSAflON
Information processing - Magnetic disk for data storage
107 500 flux transitions per track, 266 mm
devices -
(10.5 in) and 356 mm (14 in) diameter
Traitemen t de l’in forma tion - Disgue magnktique pour unit& de stockage des donndes - 707 500 transitions de flux par piste,
diamktres 266 mm (lo,5 in) et 356 mm (14 in)
First edition - 1984-12-15
U DC 681327.63 Ref. No. IS0 69024984 (E)
Descriptors : data processing, information interchange, data storage devices, magnetic disks, specifications, dimensions, tests, physical
properties, magnetic properties, surface properties, surface defects.
Price based on 14 pages
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Foreword
IS0 (the International Organization for Standardization) is a worldwide federation of
national standards bodies (IS0 member bodies). The work of preparing International
Standards is normally carried out through IS0 technical committees. Each member
body interested, in a subject for which a technical committee has been established has
the right to be represented on that committee. International organizations, govern-
mental and non-governmental, in liaison with ISO, also take part in the work.
Draft International Standards adopted by the technical committees are circulated to
the member bodies for approval before their acceptance as International Standards by
the IS0 Council. They are approved in accordance with IS0 procedures requiring at
least 75 % approval by the member bodies voting.
International Standard IS0 6902 was prepared by Technical Committee ISO/TC 97,
Information processing systems.
0 International Organization for Standardization, 1984
Printed in Switzerland
ii
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Contents
Page
1
.........................................
1 Scope and field of application
1
2 Reference .
................................................ 1
3 General requirements
2
4 Dimensions .
.............................................. 3
5 Physical characteristics
.................................... 4
6 Testing of magnetic characteristics
6
7 Surfacetests. .
.................................................. 7
8 Track quality tests.
.............................. 8
9 Acceptance criteria for magnetic surfaces.
...................................... 8
10 Defects of the magnetic surfaces
Annexes
.............................................. 13
A Air cleanliness class 100
14
...............................
B Measurement of the effective track width
. . .
III
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~-~-~~
IS0 69024984 (E)
INTER NAL DA
-s
tic disk f r data storage
lnformatio
s per track, 266 mm
devices -
m (14 in) diameter
(10.5 in) an
4 Scope and fieB General requirements
This International Standard specifies the mechanical, physical
%I Qperation and storage environment
and magnetic characteristics of a non-lubricated magnetic disk
intended for mounting in data storage devices.
3.1.1 Operation
This International Standard defines the requirements for a disk
to give satisfactory performance at 107 500 flux transitions per
The operating temperature of the air surrounding the disk shall
track.
be within the range of 15 to 57 OC (59 to 135 OF) at a relative
When used at other densities, for example 161 250 fiux transi- humidity of 8 to 80 %. The wet bulb temperature shall not
tions per track, equivalent performance may require changes to exceed 26 OC (79 OF). The air surrounding the disk shall be of
the mechanical, magnetic and electrical criteria. cleanliness class 100, as defined in annex A.
Two types are specified, Type A and Type B, which have the
3.1.2 Storage
same magnetic characteristics and are related to the same stan-
dard reference surface. They differ only with regard to their
The storage temperature shall be within the range - 40 to
outer diameter and some related numeric values.
+ 65 OC ( -- 40 to + 150 OF) at a relative humidity of 8 to
A disk is in conformance with this International Standard when
80 %. The wet bulb temperature shall not exceed 30 OC
it satisfies all requirements for Type A or all requirements for
(86 OF). Under no circumstances shall condensation on the disk
Type 6.
be allowed to occur.
NOTE - The original design of the subject of this international Stan-
Storage under the extreme conditions of the above range is not
dard was made using the Imperial measurement system. Some later
recommended. A temperature gradient of more than IO OC
developments, however, have been made using SI units. In the pro-
(18 OF) per hour should be avoided.
cess of conversion into the alternative system, values may have been
rounded. Therefore, the two sets of figures are consistent with, but not
exactly equal to, each other. Either set may be used, but the two shaii To prevent corruption of data, the ambient stray magnetic field
be neither mixed nor reconverted.
intensity at the surface of the disk shall not exceed 4 000 A/m.
When heads are present, the general ambient field shall be
reduced to take account of the concentrating effect of the core
of the head.
2 Reference
- Methud of indicating surface
IS0 1302, Technical drawings
NOTE - This will usually require the limitation of the allowed ambient
texture on drawings. field to the range of 300 to 2 000 A/m.
1
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IS0 69024984 (E)
3.2 Test conditions The circumference of the inner edge shall be contai
tween two concentric circles 25 pm (1 000 pin) apart.
Unless otherwise stated, measurements shall be carried out at
23 - + 3 OC (73 + 5 OF), 40 to 60 % relative humidity after a
4.2 Outer diameter
period of acclimatization during which condensation on the
disk shall not be allowed to occur. Tests requiring the use of
The outer diameter of the disk shall be
heads shall be performed in air of cleanliness class 100.
For Type A :
3.3 Material
356,24 + 0,13 mm (14.025 + 0.005 in)
d3A =
The disk may be constructed from any suitable material so long
as the dimensional, inertial and other functional requirements
For Type B :
of this International Standard are maintained.
dsB = 266,70 + 0,13 mm (10.500 + 0.005 in)
3.4 Coefficient of thermal expansion
the outer
The circumference of edge shall be conta
The coefficient of thermal expansion of the disk material shall
tween two concentric circles 25 000 pin) apart.
pm (1
be
4.3 Concentricity
AL 1
k7 - h5
--
K-1 =
(24 z!z 1) x lo-6 K-1
-X
LAt - L
42
The centre of the circumference of the outer edge of the disk
shall be contained in a circle of diameter 50 pm (0.002 0 in)
concentric with the centre of the circumference of the inner
pet-OF = (13,3 + 0,5) x IO-6perOF
edge.
1
The sample length L is equal to
4.4 Thickness
L57 + 45
The thickness of the disk shall be
2
("- : Ls)
= 1,905 + 0,025 mm (0.075 + 0.001 in)
e
where L, (L135) and L,, (LB) are the lengths at 57 OC (135 OF)
and 15 OC (59 OF), respectively.
4.5 Edge chamfer (figure 3)
3.5 Surface identification
For a distance
The direction of relative motion between head and disk shall be
I < I,3 mm (0.05 in)
consistent. The disk surface that is to rotate counter-clockwise
shall be identified.
from the edges of the disk, the disk contour shall be relieved
within the extended boundaries of the disk surfaces. In order to
4 Dimensions (see figures 1 to 3)
avoid unbalance, the chamfer shall be uniform at all points on
the circumference.
For measurement of the radii indicated hereafter, the disk shall
be mounted on a reference hub (see figure 1) having a
diameter, measured at 23 If: 0,5 OC (73 + 1 OF), of
4.6 Clamping area
On both sides of the disk, the clamping area shall be an area
d, = 168,255 _
i o,. mm (6.624 2 _ i ooo 4 in)
.
I
free of magnetic coating, Ii mited by the inner edge and a radius
l-2 :
and an outer radius
r2 > 91,0 mm (3.53 in)
= 90,s + 0,l mm (3.563 + 0.004 in)
r1
Between r2 and the start of the chamfer, the variation of the
All radii are referred to the axis of symmetry of this reference
disk thickness shall not exceed 7,5 pm (300 pin).
hub. The coefficient of thermal expansion of the material of the
reference hub shall be that specified in 3.4.
4.7 Location of magnetic surfaces
4.1 Inner diameter
On both sides of the disk, the area of magnetic surface, over
The inner diameter of the disk, measured at 23 k 0,5 OC
which heads may fly, shall extend from an inside radius r3 to an
(73 + 1 OF), shall be
outside radius r4 :
d2 = 168,280 + ito5’ mm (6.625 2 + i*Oo2’ in) r3 < 94,0 mm (3.70 in)
2
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IS0 69024984 (El
For Type A : 5.3.2 Axial runout
r4A > 176,0 mm (6.93 in) The axial runout at any rotational frequency up to the maximum
frequency (see 5.2) shall not exceed 0,lO mm (0.004 in), total
For Type B : indicator reading. Moreover, every point of each surface of the
disk shall be located between two planes perpendicular to the
r4B > 131/i mm (5.17 in) axis of the reference hub and distant from each other by
OJO mm (0.004 in).
As this test is intended to measure the flatness of the disk,
5 Physical characteristics
measures shall be taken to counteract the droop of the disk due
to gravity.
5.1 Moment of inertia
5.3.3 Velocity of axial runout
The moment of inertia of the disk shall not exceed :
With the disk revolving at 3 600 _+ 36 r/min, the velocity of ax-
For Type A : ial runout of the recording disk surfaces shall not exceed
51 mm/s (2.0 in/s). It shall be measured within the band width
defined by a low-pass filter with a cutoff frequency of 2,2 kHz
8,0 gmrn2 (27.3 Ib=in2)
and a high frequency roll-off of 18 dB/octave. The probe
diameter shall be I,7 mm (0.067 in).
For Type B :
2,5 g.rn2 (8.53 Ib+G)
Acceleration of axial runout
5.3.4
With the disk revolving at 3 600 + 36 r/min, the acceleration
5.2 Maximum rotational frequency
of axial runout shall not exceed 51 m/s2 (2 000 in/$) within
the measurement band-width defined by a low-pass filter with a
of withstandi ng the effect of at
The disk shall be capable
cut-off frequency of 5 kHz and a high frequency roll-off of
a rotational frequency of 4 000 r/min.
18 dB/octave.
5.3 Runout
5.3.5 Radial runout
The radial runout of the disk depends on the concentricity (see
4.3) and circularity (see 4.1 and 4.2) of the inner and outer
edges, as well as on the clamping conditions in the device in
which it is mounted. It is therefore not specified by this Inter-
The requirements of 5.3.2, 5.3.3 and 5.3.4 shall be met at any
national Standard.
radius between radii r3 and r4.
5.4 Surface roughness
5.3.1 Test spindle requirements and clamping
conditions (figure 1)
5.4.1 Magnetic surfaces
The disk shall be clamped on the reference hub by a force
The finished magnetic surfaces shall have a surface roughness
less than 0,035 pm (1.38 pin), arithmetic average, with a maxi-
F= 1 500 + 200 N (340 + 45 Ibf)
mum deviation in height of 0,38 pm (15 pin) from the average,
when measured with a stylus of radius 2,5 pm (100 pin) with a
evenly applied over an annular surface on the disk defined by
0,5 mN load, and a 750 pm (0.03 in) upper cut-off range.
= 86,5 mm (3.41 in)
r5
The finished magnetic surfaces shall have an undulation profile
with a peak-to-peak amplitude of less than 0,15 pm (6.0 pin)
= 90,4 mm (3.56 in)
r6
when measured over a radial length of 4,8 mm (0.19 in) with a
stylus of radius 2,5 pm (100 pin) with a 0,5 mN load, and a
The finish of the surface of the reference hub on which the disk
lower cut-off range of 250 pm (0.01 in).
rests shall be of class N 5 [maximum arithmetical deviation
0,4 pm (16 pin)] as defined in IS0 1302.
5.4.2 Clamping area
At any rotational frequency up to the maximum frequency (see
5.2), the axial runout of the reference hub shall not exceed
The finished surface of the clamping area shall have a surface
1 ,O pm (40 pin).
roughness less than 0,8 pm (30 pin), arithmetic average, with a
maximum deviation in height of 2,0 pm (80 pin) from the
The radial runout of the reference hub, i.e. the total indicator
average, when measured with a stylus of radius 2,5 pm
reading, as referenced to the centre of rotation of the reference
(100 pin) with a 0,5 mN load, and a 750 pm (0.03 in) upper cut-
hub is included in the tolerance of rl.
off range.
3
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IS0 69024984 (E)
For Type A :
5.5 Cleaning of the magnetic surfaces
The magnetic surfaces of the disk shall not be adversely af-
166,4 mm (6.55 in)
%A =
fected by a 91 % solution of isopropyl alcohol (made from
reagent grade isopropyl alcohol mixed with 9 % distilled or
For Type B :
deionized water by volume) when used for cleaning.
= 124,7 mm (4.91 in)
r8B
5.6 Durability of the magnetic surfaces
The nature of the coating shall be such as to assure wear 6.2.4 Location of the line of access
resistance under operating conditions and maintenance of
adhesion and abrasive wear resistance.
The line of access shall be radial.
5.7 Head/disk gliding requirements
6.2.5 Recording offset angle
The magnetic surface shall be free of surface defects which
At the instant of writing or reading a magnetic transition, the
would cause head to disk contact when the head is flying at
transition may have an angle of 60’ maximum with the line of
0,61 pm (24 pin) minimum at radius r3, and proportionally in-
access.
creasing in flying height to 084 pm (33 pin) minimum at
radius r4.
63 . Standard reference surface
5.8 Discharge path
6.3.1 Characteristics
The disk shall allow flow of electrical charges from the
magnetic surface to the clamping surface.
The Standard reference surface shall be characterized at the
three following test radii
6 Testing of magnetic characteristics
= 107,96 mm (4.250 in)
r9
6.1 General conditions
= 124,OO mm PM82 in)
r10
6.1 .I Rotational frequency
= 163,69 mm (6.445 in)
r11
The rotational frequency shall be 3 600 + 36 rlmin in any test
period.
6.1.2 Ambient stray magnetic field
The intensity of the ambient stray magnetic field shall not
exceed 800 A/m. 2,75 mV at radius r10
3,80 mV at radius rlI
6.2 Track an.d recording conditions
When recorded at 2f (see 6.91, using the test the track
6.2.1 Width of tracks
shall be
average amplitude
The recorded track width shall be
1,70 mV at radius rg
51 - + 4 pm (2 000 + 160 PinI
2,15 mV at radius r10
of measuring the effective track
A suggested method
contained in annex B
3,00 mV at radius rII
6.2.2 Track spacing
6.3.2 Secondary standard reference surface
...
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