SIST EN 28860-1:1997

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Information processing - Data interchange on 90 mm (3.5 in) flexible disk cartridges using modified frequency modulation recording at 7 958 ftprad, 5,3 tpmm (135 tpi) on both sides - Part 1: Dimensional, physical and magnetic characteristics (ISO 8860-1:1987)Informationsverarbeitung - Datenaustausch auf 90 mm (3.5 mm) Disketten mittels modifizierter Frequenzmodulationsaufzeichnung bei 7 958 ftprad, 5,3 tpmm (135 tpi), auf beiden Seiten - Teil 1: Mechanische, physikalische und Größenanforderungen (ISO 8860-1:1987, Ausg. 1)Traitement de l'information - Echange de données sur cartouches a disquette de 90 mm (3,5 in) utilisant un enregistrement a modulation de fréquence modifiée a 7 958 ftprad, 5,3 tpmm (135 tpi) sur deux faces - Partie 1: Caractéristiques dimensionnelles, physiques et magnétiques (ISO 8860-1:1987, éd. 1)Information processing - Data interchange on 90 mm (3.5 in) flexible disk cartridges using modified frequency modulation recording at 7 958 ftprad, 5,3 tpmm (135 tpi) on both sides - Part 1: Dimensional, physical and magnetic characteristics (ISO 8860-1:1987, ed. 1)35.220.21Magnetni diskiMagnetic disksICS:Ta slovenski standard je istoveten z:EN 28860-1:1989SIST EN 28860-1:1997en01-december-1997SIST EN 28860-1:1997SLOVENSKI
STANDARD



SIST EN 28860-1:1997



SIST EN 28860-1:1997



SIST EN 28860-1:1997



INTERNATIONAL STANDARD INTERNATIONAL ORGANIZATION FOR STANDARDIZATION ORGANISATION INTERNATIONALE DE NORMALISATION MEXflYHAPOC\HAR OPTAHM3Auklfl l-l0 CTAHfiAPTM3A~MM Information processing - Data interchange on 90 mm (3.5 in) flexible disk cartridges using modified frequency modulation recording at 7 958 ftprad on 80 tracks on each side - Part 1 : Dimensional, physical and magnetic characteristics Traitemen t de Rnformation - ichange de don&es SW cartouches h disquette de 90 mm (3,5 in) utilisant un enregistrement A modulation de frhquence modifihe (MFM) a 7 958 ftprad sur 810 pistes sur chaque face - Partie 7 : Caract&istiques dimensionnelles, physiques et magn&iques IS0 8860-l First edition 1987-07-01 Reference number IS0 8860-l : 1987 (E) SIST EN 28860-1:1997



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 8860-l was prepared by Technical Committee ISO/TC 97, Information processing systems. Users should note that all International Standards undergo revision from time to time and that any reference made herein to any other International Standard implies its latest edition, unless otherwise stated. @ International Organization for Standardization, 1987 l Printed in Switzerland ii SIST EN 28860-1:1997



IS0 8860-I : 1987 (El Contents Page 0 Introduction . I Scope and field of application . 2 Conformance . 3 References . 4 Definitions. . 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10 4.11 4.12 4.13 4.14 4.15 4.16 4.17 4.18 recording disk . hub . shutter . liner. . case. . Master Standard Reference Flexible Disk Cartridge . Secondary Standard Reference Flexible Disk Cartridge . Typical Field . Reference Field . Test Recording Current. . Standard Reference Amplitudes ERAS) . Average Signal Amplitude . in-contact . side . direction of rotation. . index. . formatting . initialization. . 5 General description . 5.1 Figures . . 3 1 1 1 1 3 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 2 2 2 . . . III SIST EN 28860-1:1997



IS0 8860-l A987 (E) 5.2 Main elements . 5.3 Description . 6 General requirements . 6.1 Environment and transportation . 6.2 Materials . 7 Dimensional characteristics. . 7.1 Case . 7.2 Liner . 7.3 Disk . 7.4 Hub. . 7.5 Optional handling notches . 7.6 Interface between cartridge and drive. . : . 7.7 Compliance . 8 Physical characteristics . 8.1 Inflammability. . 8.2 Coefficient of linear thermal expansion of the disk . 8.3 Coefficient of linear hygroscopic expansion of the disk . 8.4 Torque . 9 Magnetic characteristics . 9.1 Recordingarea . 9.2 Trackgeometry. . 9.3 Functional testing . 2 2 2 2 3 3 3 5 5 5 6 6 6 6 6 6 6 6 7 7 7 7 Annexes A Test for compliance . 14 6 Measurement of light transmittance . 16 C Method for measuring the effective track width . 18 D Cartridge distortion test gauge. . 19 E Method for measuring peak shift . 20 iv SIST EN 28860-1:1997



INTERNATIONAL STANDARD IS0 8860-l : 1987 (E) Information processing - Data interchange on 90 mm (3.5 in) flexible disk cartridges using modified frequency modulation recording at 7 958 ftprad on 80 tracks on each side - Part 1 : Dimensional, physical and magnetic characteristics 0 Introduction IS0 8860 specifies the characteristics of 90 mm (3.5 in) flexible disk cartridges recorded at 7 958 ftprad using modified fre- quency modulation (MFM) recording on 80 tracks on each side. IS0 8860-2 specifies the track layout, the track format and the characteristics of the recorded signals. IS0 8860-l and IS0 88602, together with the labelling scheme specified in IS0 9293, provide for full data interchange between data processing systems. 1 Scope and field of application This part of IS0 8860 specifies the dimensional, physical and magnetic characteristics of the cartridge, so as to provide physical interchangeability between data processing systems. NOTE - Numeric values in the SI and/or Imperial measurements system in this part of IS0 8860 may have been rounded off and therefore are consistent with, but not 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 SI units. 2 Conformance A 90 mm (3.5 in) flexible disk cartridge shall be in conformance with this part of IS0 8860 if it meets all mandatory requirements contained herein. 3 References IS0 683-13, Heat-treated steels, alloy steels and free-cutting steels - Part 73 : Wrought stainless steels. IS0 0860-2, Information processing - Data interchange on 90 mm (3.5 in) flexible disk cartridges using modified frequency modulation recording at 7 958 ftprad on 80 tracks on each side - Part 2 : Track format. IS0 9293, Information processing - Volume and file structure of flexible disk cartridges for information interchange. 4 Definitions For the purpose of this International Standard the following definitions apply. 4.1 recording disk : A flexible disk which accepts and re- tains, on the specified side or sides, magnetic signals intended for input/output and storage purposes. 4.2 hub : A centring and referencing device attached to the centre of the disk which allows torque to be transmitted to the disk. It ensures centring of the disk on the drive shaft in a unique angular position. 4.3 shutter : A device which uncovers the head windows upon insertion, and automatically covers them upon removal from the drive. 4.4 liner : Suitable material positioned between the case and the disk to provide cleaning action and protection from abrasion. 4.5 case : A protective enclosure including a shutter mechanism and a write-inhibit hole. 4.6 Master Standard Reference Flexible Disk Car- tridge : A reference flexible disk cartridge selected as the stan- dard for reference fields, signal amplitudes, resolution, peak shift and overwrite. Track 00 and track 79 on both sides are declared as reference tracks. The reference tracks are calibrated at 600 r/min. The calibration is also valid at 300 r/min. NOTE - This master standard has been established by the Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, D-3300 Braunschweig, Germany, F. R. 4.7 Secondary Standard Reference Flexible Disk Car- tridge : A flexible disk cartridge the performance of which is known and stated in relation to that of the Master Standard Reference Flexible Disk Cartridge. NOTE - Secondary Standard Reference Flexible Disk Cartridges can be ordered from PTB Lab. 1.41 under Part Number RM 8860 as long as available. It is intended that these be used for calibrating further car- tridges for use in routine calibration. 1 SIST EN 28860-1:1997



IS0 8860-l : 1987 (E) 4.8 Typical Field : In the plot of average signal amplitude against recording field at the specified track and flux transition density, the Typical Field is the minimum field which causes a signal output equal to 95 % of the maximum Average Signal Amplitude. 5 General description 5.1 Figures In figures 1 to 5 : - Figure 1 - Figure 2 - Figure 3 - Figure 4 - Figure 5 shows Side 0 and enlarged through the location holes; cross-sections 4.9 Referent e Field : The typical field of the dard Reference Flexible Disk Cartridge. Master Stan- shows Side 1; There are two Reference Fields, one for each side. shows at a larger scale Side 0 without shutter; the upper part of 4.10 Test Recording Current : The current between 148 % and 152 % of the current which produces the Reference Field at test frequency If on track 00. shows the disk with hub; shows the interfa and the dri ve. ce between the cartridge There are two Test Recording Currents, one for each side. 5.2 Main elements 4.11 Standard Reference Amplitudes (SRAs) : The Average Signal Amplitudes derived from the reference tracks of the Master Standard Reference Flexible Disk Cartridge using the Test Recording Current. The main elements of the flexible disk cartridge are - the recording disk; There are four SRAs, two for each side. - the liner, SRA1/ is the Average Signal Amplitude from a recording writ- ten using Test Frequency lfat Track 00. - the case. 5.3 Description SRAZS is the Average Signal Amplitude from a recording writ- ten using Test Frequency 2f at Track 79. The cartridge is of a substantially square form. It includes a central hole on one side, a heat window on both sides and a write-inhibit hole. 4.12 Average Signal Amplitude : For a track : the arithmetically averaged value of the output voltages measured peak-to-peak over the whole track. The liner is provided between the case and the disk. It com- prises two layers of material between which the disk lies. The disk has a central hole with a metal hub attached. 4.13 in-contact : An operating condition in which the magnetic surface of the disk is in physical contact with the magnetic heads. 6 General requirements 4.14 side : Side 0 is the side engaged by the spindle. Side 1 is the opposite side. 61 . Environment and transportation 6.1.1 Testing environment 4.15 direction of rotation : The direction be counter-clockwise when looking at Side 0. of rotation shall Tests and measurements made on the cartridge to check the requirements of this International Standard shall be carried out under the following conditions : temperature : 23 + 2 OC (73 + 4 “F) 4.16 index : The point on a track beginning and the end of the track. which determines the relative humidity : 40 to 60 % 4.17 formatting : Writing the proper control information, establishing the physical cylinders and the addresses of physical records on the surfaces of the flexible disk. conditioning before testing : 24 h minimum For the tests specified in 9.3 the temperature and relative humidity shall be measured in the air immediately surrounding the cartridge drive. For all other tests the temperature and relative humidity shall be measured in the air immediately sur- rounding the cartridge. 4.18 initialization : Writing any information initially required to be on the flexible disk cartridge, for example the Volume Label, prior to the commencement of general processing use. 2 SIST EN 28860-1:1997



IS0 8860-l : 1987 (El The stray magnetic field at any point on the disk surface, including that resulting from the concentrating effect of the recording head, shall not exceed 4 000 A/m (50 Oe). maximum rate of temperature change : 20 OC (36 OF) per hour relative humidity : 8 to 90 % There should be no deposit of moisture on or in the cartridge. 6.1.2 Operating environment 6.2 Materials Cartridges used for data the following conditions In terchange shall be operated under 6.2.1 Case temperature : 10 to 60 OC (50 to 140 OFI The case, which may be constructed from any suitable material, shall comply with the requirements of annex A. relative humidity : 8 to 80 % wet bulb temperature : less than 29 OC (85 OFI 6.2.2 Liner The temperature and relative humidity shall be measured in the air immediately surrounding the cartridge. It is recommended that the rate of change of the temperature should not exceed 20 OC (36 OF) per hour. The material of the liner shall without damage to the disk. be able to retain dust or debris 6.2.3 Disk NOTE - For reliable interchange, it is recommended that the temperature and relative humidity conditions when reading are not the opposite extreme to the conditions when writing. The disk shall be constructed from any suitable material (for example bi-axially oriented polyethylene terephthalate) coated with a flexible layer of magnetic material. There shall be no deposit of moisture on or in the cartridge. 6.2.4 Hub The stray magnetic field at any point on the disk surface, in- cluding that resulting from the concentrating effect of the recording head, shall not exceed 4 000 A/m (50 Oe). The hub shall be made from any suitable material (for example stainless steel all oy in compliance with IS0 683-l 3, type 81. 6.1.3 Storage environment 7 Dimensional characteristics During storage conditions : the cartridges shall be kept under the followi w The dimensions of the cartridge are referred to two reference axes X and Y, i.e. two lines in space intersecting at right angles. The plane they define is the Reference Plane XY of the car- tridge. temperature : 4 to 53 OC (39 to 127 OFI relative humidity : 8 to 90 % 7.1 Case There shall be no deposit of moisture on or in the cartridge. 7.1.1 Shape (see figure 1) The ambient stray magnetic field shall not exceed 4 000 A/m (50 Oe). The case shall be of rectangular form, its sides shall be 4 = 94, 0 + 0,3 mm (3.700 + 0.012 in) NOTE - Cartridges which have been stored at temperatures and humidities exceeding the operating conditions may exhibit degraded performance characteristics. Such cartridges should be subjected to a conditioning period of not less than 24 h within the operating environ- ment prior to use. /2 = a0 -0,l +Ot4 mm 3.540 +-~j~~ in ( . > The radius of three of its corners shall be '1 = 2,0 + 1,O mm (0.079 + 0.040 in) - 6.1.4 Transportation Responsibility for ensuring that adequate precautions are taken during transportation shall be with the sender. The cartridge shall be in a protective package free from dust or extraneous matter. It is recommended that a sufficient space exists be- tween cartridge and outer surface of the final container, so that risk of erasure due to stray magnetic fields will be negligible. The angle of its fourth corner shall be co= 45O + 2O 7.1.2 Thickness (see figure 2) In the area extending 8,5 mm (0.335 in) from each of the two edges as shown in figure 2, the thickness of the case shall be 9 = 3,3 + 0,2 mm (0.130 IfI 0.008 in) It is recommended exceeded : that the following conditions should not be temperature : -40 to 60 OC ( -40 to 140 OF) SIST EN 28860-1:1997



IS0 8860-l : 1987 (E) When the cartridge is inserted in the test gauge specified in annex D, a force not exceeding 0,2 N (0.69 ozf), applied to the centre of the back edge shall cause the cartridge to pass through the gauge. The edge radius shall be r2 = 0,40 + 0,25 mm (0.150 + O.c)lO in) 7.1.3 Hub access hole (see figure I) On Side 0 there shall be a hub which shall be access hole the diameter of dl = 26,50 mm min. (I .043 in min.) The position of the centre of this hole shall be defined by 13 = 40,OO * 0,15 mm (I .575 + 0.006 in) /J = 31,OO ,+ 0,15 mm (1.220 + 0.006 in) 7.1.4 Locating holes (see figures 1 and 3) 7.1.4.1 Primary locating hole The centre of the primary locating tion of Reference Axes X and Y. hole shall be at the intersec- Its diameter shall be d2 = 3,6 rt 0,l mm (0.142 + 0.004 in) The dimensions shall be of its cross-section A-A in figure I) d, = I,5 mm min. (0.059 in min.) l8 = 0,2 k 0,l mm (0.010 + 0.004 in) /g = I,0 mm min. (0.039 in min.) ho = 2,5 mm min. (0.098 in min.) 7.1.4.2 Secondary locating hole The centre of the secondary locating hole shall be Axis X, its distan ce from Reference Axis Y shall Reference 15 = 80,O + 0,2 mm (3.150 + 0.008 in) It shall have a substantially rectangular shape. Its short axis shall be (cross-section B-B in figure I) I6 = 3,6 + 0,l mm (0.142 + 0.004 in) Its long axis shall be ,-r = 4,4 ,+ 0,2 mm (0.173 + 0.008 in) The dimensions d3, /& 19 and lto of the cross-section secondary locating hole are as specified in 7.1.4.1. 7.1.5 Label area 7.1.5.1 Side 0 (see figure I) The locations and dimensions of the label area of Side 0 shall be Ill = 3,5 mm min. (0.138 in min.) [12 = 76,5 mm max. (3.012 in max.) I14 = 60,O mm min. (2.362 in min.) 7.1.5.2 Side 1 (see figure 2) The locations and dimensions of the label area of Side 1 shall be Ill = 3,5 mm min. (0.138 in min.) I12 = 76,5 mm max. (3.012 in max.) 113 = 20,O mm min. (0.787 in min.) 7.1.6 Head windows (see figure 3) The locations and the dimensions of the two head windows are specified by the same set of dimensions. 7.1.6.1 Location The location of the head windows shall be defined by I15 = 12,3 mm min. (0.485 in min.) I16 = 11,5 mm min. (0.45 in min.) 117 = 35,5 + 0,2 mm (1.400 * 0.008 in) 7.1.6.2 Dimensions The width of the head windows shall be I18 = 9,00 rf: 0,20 mm (0.354 + 0.008 in) The radius of their corners shall be r3 = 0,5 + 0,l mm (0.020 + 0.004 in) The radius of their upper edge shall be r4 = 8,85 mm min. (0.348 in min.) 7.1.7 Write-inhibit hole (see figure 2) 7.1.7.1 Location The centre of the write-inhibit hole shall be on Reference Axis Y. Its distance from Reference Axis X shall be 119 = 67,75 + 0,25 mm (2.667 + 0.010 in) SIST EN 28860-1:1997



IsO886@1 :1987 E) 7.1.7.2 Dimensions The dimensions of the write-inhibit hole shall be 120 = 3,5 mm min. (0.138 in min.) /21 = 4,0 mm min. (0.157 in min.) 7.1.7.3 Use The write-inhibit hole is intended for use either with a mechanical switch or with an optical detector so that only when the hole.is covered is writing on the disk possible. When covered, the closure device shall not extend outside the Reference Plane nor shall it deflect by more than 0,3 mm (0.012 in) from the Reference Plane inside the case under the action of a force of 3 N (0.67 Ibf). Also when covered, the light transmittance of the write-inhibit hole area shall not exceed 1 %, when measured with an optical system as described in annex B. 7.1.8 Profile of the shutter edge of the case (see figures 1 and 3) The edge on which the shutter is mounted shall have a profile defined by the following dimensions : 122 = 80,O + 0,2 mm (3.150 + 0.008 in) l23 = 76,0 + 0,3 mm (2.990 + 0.012 in) I24 = 68,0 + 0,3 mm (2.680 + 0.012 in) I25 = 64,50 + 0,35 mm (2.540 + 0.014 in) [26 = 57,00 + 0,35 mm (2.240 It 0.014 in) I27 = 55,5 +, 0,6 mm (2.180 ,+ 0.025 in) 128 = 3,5 mm min. (0.137 in min.) 1+2g = 17,5 + 0,2 mm (0.690 + 0.008 in) [30 = 17,00 + 0,15 mm (0.669 + 0.006 in) 131 = 1550 * 0,25 mm (0.61 & 0.010 in) l45 = 12,50 + 0,25 mm (0.492 If: 0.010 in) a = 45O + 2O p = 135O ,+ 2O cc)= 45O + 2O 7.1.9 Shutter (see figures 2 and 3) The shutter shall slide upon insertion of the cartridge into the drive so as to uncover the head windows, and close automati- cally upon removal. The maximum resistance force at the fully open position shall be 1 N, and the minimum resistance force at the fully closed position shall be 0,2 N. The path along which the shutter can slide is defined by I25 and 1.28. In the open position of the shutter, the distance from its leading edge to Reference Axis Y shall be [32 = 53,75 + I,25 mm (2.116 + 0.050 in) The width of the windows of the shutter shall be & = 12,0 + 0,2 mm (0.472 + 0.008 in) NOTE - It is a requirement that the drive shall provide a mechanism whereby correct insertion of the cartridge into the drive causes the shutter to slide so as to uncover the head windows. 7.2 Liner No part of the liner shall protrude by more than 0,2 mm (0.008 in) into the head access windows. 7.3 Disk (see figure 4) 7.3.1 Diameter The diameter of the disk shall be d4 = 85,8 + 0,2 mm (3.378 + 0.008 in) 7.3.2 Thickness The thickness of the disk shall be e2 = 0,080 + 0,008 mm (0.003 1 ,+ 0.000 3 in) 7.4 Hub (see figure 4) The hub shall have a central part and a flange. 7.4.1 Dimensions The diameter of the central part shall be The diameter of the flange shall be d6 = 31,15 mm max. (1.226 in max.) The distance from the surface of the central part of the hub to the surface of Side 0 of the disk shall be z3(q = I,36 + 0,lO mm (0.053 + 0.004 in) when measured at a radius r7 r7 = 14 mm nom. (0.55 in nom.) 7.4.2 Hub orientation holes (see figure 4) The hub shall have two orientation holes. The first one at its centre, the second off-centre. 5 SIST EN 28860-1:1997



IS0 8860-l : 1987 (E) 7.4.2.1 First orientation hole 7.6 Interface (see figure 5) between cartridge and drive The first orientation hole shall have a square form defined by When the cartridge is inserted in the drive, the drive spindle shall engage the cartridge as shown in figure 5. The hub is held against the drive spindle by means of a magnetic attraction force. When in this position the distance between the hub sur- face on Side 0 and plane XY shall be I35 = 4,00 mm min. (0.15 in min.) The position of the centre of rotation of the disk is defined by /36 = 1,995 5 mm (0.078 56 in) /#j = 0,3 mm nom. (0.012 in nom.) measured from two sides of the hole. This centre of rotation shall be within 0,5 mm (0.020 in) of the geometric centre of the disk. The inside dimensions of the case on Side 1 shall be e3 = 1,3 + 0,l mm (0.051 + 0.004 in) The radius of the four corners of this hole shall be r5 = 1,0 + 0,3 mm (0.040 + 0.012 in) with the exception of the annular where the thickness shall be by ld7 and /M 7.4.2.2 Second orientation hole e4 = 2,5 mm max. (0.098 in max.) The position and dimensions of the sides of the rectangular second orientation hole are referred to two radial lines A and B that are perpendicular to each other. Their positions shall be , specified by I47 shall be sufficiently large to ensure that the circumference of the disk shall not touch the inside edges of the case. The value of 147 specified below is a recommended value, therefore it is stated without tolerance. Y = 15O + 3O I47 = 22,6 mm (0.890 in) The length of the sides of this hole shall be 14 = 21,7 + 0,2 mm (0.854 + 0.008 in) 137 = 8,0 + 0,3 mm (0.315 + 0.012 in) 138 = 4,5 mm min. (0.177 in min.) 7.7 Compliance When the cartridge is constrai ned in the manner speci fied in annex A, the cartridge shall be in contact with posts Pl to P4. These sides distance shall be to lines A and B, respectively, at a 139 = 2,0 + 0,2 mm (0.079 + 0.008 in) 8 Physical characteristics lJ(j = 10,OO + 0,15 mm (0.393 + 0.006 in) 8.1 Inflammability The radius of one corner of this hole shall be The disk, case and liner components shall be made from materials that, if ignited from a match flame, do not continue to burn in a still carbon dioxide atmosphere. r6 = 2,0 + 0,l mm (0.079 f: 0.004 in) The radius of the three other corners shall be r5 = 1,0 * 0,3 mm (0.040 + 0.012 in) 8.2 Coefficient of linear thermal expansion of the disk 7.5 Optional handling notches (see figures 1 and 2) The coefficient of thermal expansion of the disk shall be Two handling notches are permitted. satisfy the following requirements. If present they shall (17 + 8) x 1O-6 per degree Celsius 8.3 Coefficient of linear hygroscopic expansion of the disk Their centres shall be Axis X at a distance on a line parallel to, and above, Reference The coefficient of hygroscopic expansion of the disk shall be l41 = 750 + 0,15 mm (0.295 + 0.006 in) (0 to 15) x 10B6 per percent of relative humidity Their dimensions shall be /42 = 3,0 mm min. (0.118 in min.) 8.4 Torque la= I 4 2 ,+ 0,2 mm (0.165 + 0.008 in) 8.4.1 Starting torque Their depth below the Reference Plane shall be The starting torque, without the heads loaded, shall not exceed 0,006 Nom (0.85 ozfgin). la = 2,0 mm min. (0.08 in min.) SIST EN 28860-1:1997



Is0 8860-l : 1987 E) 8.4.2 Running torque! without heads loaded The torque necessary to turn the disk shall be in the range 0,000 5 N-m to 0,002 5 Nom (0.071 to 0.354 ozfain) when the cartridge is in operation at a speed of 300 + 3 r/min and 600 f: 6 r/min. 9 Magnetic characteristics 9.1 Recording area On each side, the magnetic properties specified shall be uniform in the recording area which shall be the area limited by two radii : 42,0 mm min. (1.65 in min.) 20,6 mm max. (0.81 in max.) 9.2 Track geometry 9.2.1 Number of tracks In the recording area there shall be 80 discrete concentric tracks on each side of the disk. The distance between centrelines of adjacent tracks shall be 0,187 5 mm (0.007 38 in). The resulting track density is 533 tpmm (135.467 tpi). 9.2.2 Width of tracks The width of a recorded track shall be 0,115 + 0,008 mm (0.004 5 + 0.000 3 in) The method of measuring effective track width is given in annex C. 9.2.3 Track location 9.2.3.1 Nominal locations The nominal radius (I?,) of the centrelines of all tracks shall be calculated by using the formula 4 = X - 0,187 5 n (R n = X - 0.007 38 n) where n is the track number : n = 00 to 79. X= 39,500 0 mm (1.555 1 in) for Side 0; X= 38,000 0 mm (1.496 1 in) for Side 1. 9.2.3.2 Track location tolerance For testing purposes, the centrelines of the recorded tracks shall be within + 0,020 mm ( + 0.000 8 in) of the nominal posi- tions, when measured in the testing environment (see 6.1.1). 9.2.3.3 Line of access of the read/write heads The line of access of the read/write heads is a line parallel to a radial line and spaced 0,35 mm (0.013 8 in) from it (see IS0 8860-2, sub-clause 4.3). 9.2.4 Track number The track number shall be a two-digit decimal number (from 00 to 79 for each side) which identifies the tracks consecutively, starting at the outermost track (00). 9.3 Functional testing For the purpose of the following tests the same drive unit shall be used for writing and reading operations, both for the disk under test and for the Master Standard Reference Flexible Disk Cartridge. The in-contact condition shall be used. 9.3.1 Surface tests The magnetic properties of both surfaces are defined by the testing requirements given below. 9.3.1.1 Test conditions The disk shall be tested at 300 + 3 r/min or 600 + 6 r/min (see 5.6). The test frequencies [flux transitions per second, (ftps)] used shall be At 300 r/min : lf = 125 000 + 125 ftps 2f = 250 000 + 250 ftps At 600 r/min : lf = 250 ooo + 250 ftps 2f = 500 ooo + 500 ftps The frequency(ies) to be used is specified for each test. 9.3.1.2 Typical field The typical field of the disk under test shall be within + 20 % of the Reference Field. It shall be measured using lf on track 00 on both sides. 9.3.
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