GB/T 2950-1982 Magnetic properties of eleven-disc interchangeable disk packs
Some standard content:
National Standard of the People's Republic of China
Magnetic characteristics of interchangeable magnetic eleven-disk pack
UDC 681.327.63
GB2950-82
This standard makes necessary provisions for the magnetic properties of an interchangeable eleven-disk pack (hereinafter referred to as the disk pack) so as to ensure the interchangeability of the disk pack. All general and mechanical properties of the disk pack shall comply with the provisions of GB2310-80 "Mechanical properties of eleven-disk packs". This standard applies to disk packs used in data processing systems. This standard is formulated with reference to the performance part of the International Organization for Standardization standard ISO3564-1976 "Information processing - one-piece interchangeable disk pack - Mechanical properties and magnetic properties". Arrangement of recording surfaces and magnetic heads
Twenty recording surfaces and corresponding magnetic heads are numbered in sequence from top to bottom, and their arrangement is shown in Figure 1 and Table 1. c-
B Head collision
Eight Head Arms
Disk assembly rotation direction.
One Protection Disk
-Element Index Disk
Figure 1 Schematic diagram of recording surface and head configuration
National Standards Administration 1962-03-29 Issued
1983-01-01 Implementation
(Head or recording surface)
GB 2950-82
Configuration of head and recording surface
To: "U" in Table 丨 indicates that the head floats upward, and "D" indicates that the head floats downward. 2 Track geometry parameters
2.1 Number of tracks
Each recording surface should have 203 center circle tracks of different radii. 2.2 Track Width
After straddling erasure, the track width recorded on the disk surface should be 0.175-0.02 mm. The area between the tracks should be erased. A method for measuring the effective track width is deduced in Appendix A. 2.3 Track Position
2.3.1 Nominal Position
The nominal values of the centerline radius of each track calculated according to the geometric figure of the head-disk system in Figure 2 and the relevant constants are listed in Table 2. At 23°C, the relevant dimensional constants are specified as follows.
Head displacement increment:
S=0.2567mm.
Offset distance of the head working gap:
Far=12.125mm,
Fbr = 10.987 mm.
73The radius of the centerline of the track
R = 148.057mm.
Head deflection angle:
9 = 4°54°
Track number
H Head arm
Head write
Gap access line
-B Head slider
GB 2950—82
Add disk S
Straddle erase gap
Read/write time
On film transfer
A Magnetic sense
4 Head read/F
Gap access line
A Head slider
Figure 2 Geometry of head-disk system
Table 2 Nominal value of track radius
A Head slider track radius
166,7415
165 ,4614
16, 4372
163,6692
163,4132
163,1572
162,9012
16 2,1331
：161.8771
161,6211
1608582
160,5972
160,3412
B Magnetic fire track radius
165,9796
165,7235
64.4430
164,1869
163,9307
163,4186
182,9064
162,6503
162,3942
161,8821
161,6260||tt| |161,3699
161,1138
160,6017
Track number
A head track radius
159,8292
158, 8053
158,5493
158,0374
154,9659
154,4541
154,1981
153 ,9422
153,8863
B magnetic track radius
159,8334
159,3213
158,8092
15 8,2971
156,2487
155,7386
154,7125
154,4565
154,2004
1 53,9444
Track number
AHead track radius
153,4304
152,9185
152,150B
151,8949
151,6390
151,1272
150,8713
150,.6154
150,3695
1501 036
149,8477
149,5918
149,3360
149,0801
148,8242
148 ,0566
147,2890
147,0332
146,7773
146,5213
1460098
145 ,2423
144,9865
144,7306
114,4748
144,2190
143,963
143 ,7073
143,4515
143,1957
142,9399
142,1725
141,9167
GB 2950--82
Continued Table 2
H head track radius
153,1764
152,6644
152,4084
152,15 24
151,8963
151,6403
[51,3843
150,8723
150,6164
150,360 4
-149,5924
148,5685
148,3126
148,0566
147,2887
116,776 8
146,5209
146,2649
145,4971
145,2412
144,7293
144,4734
144,2174
143,9615
143,7056
143,1938
142,6819
142,4260
141,9142
Track number
A head track radius
141,1494
140,8936
140,3820
13 9,8705
139,3590
138,5917
138,3360
138,0802
137,5688
137 ,3130
135,2673
134,7559
134,5002
133,7332
133;4773
132,9662
132,7105
132,4549
132,1992
131,6879
131,4323
130,9210
130,6654
129,6429
B head track radius
141,1466||tt| |140,8907
140,6348
140,3789
139,8671
139,6113
139 ,0995
138,8437
138,3319
138,0761
137,5644
137,0527
136,7969
136,5410
136,2852
136,0293
135,7735||tt ||135,5177
134,7503
133,4712
133,2154
132,9597
132 ,4481
131,4250
130,9135
130,6577
130,4020
129,890 5
Track number
A head magnetic reversal radius
December, 8761
128,1093
127,5982
127, 3 426
127,0870
126,5759
125,8093
125,2982
125,0427| |tt||124,5316
124,0206www.bzxz.net
123,2541
122,.9986
122,4876||tt ||122,2321
2.3.2 Track position tolerance
GB2950—82
Continued Table 2
Daily head track radius
128,6118| |tt||128,1004
127,8446
126,8218
125,5434
125,2877| |tt||1250320
124,7764
122,7312
Track number
A head track radius
121,976 6
121,7213
121,4657
120,6994
120,1885
119,9331||tt ||119,6776
119,4222
119,1668
118,4006
118,1452
11 7,6345
117,1237
116,6130
116,1023
B head track half selection
121.708?
121,4531
121,1975
120,9419
120,6863
120,4307
119,9196|| tt||119,6640
119,4084
119,1529
118,3862
1181306
115,5754
In At 23°C, the deviation of the measured position of the recorded track centerline from the nominal position should be within ±0.025mm. Since track 73 is used to calibrate the drive, the deviation of track 73 should be within ±0.0075mm. ② At other degrees (within the range specified in GB 2310-80), the nominal position of the track centerline can be calculated using the linear expansion coefficient 24×10'/T.
2.3.8 Recording deflection angle| |tt||At the moment of writing to reading, the angle formed by the head access line specified in the magnetization reversal diagram 2 is 451'+302.4 marks
Use the following marks to test.
2.4.1 Track Mark
Track marks are represented by three-digit decimal numbers (000 to 202). Each recording surface is numbered sequentially from the outermost track to the innermost track. 2.4.2 Recording Surface Mark
As shown in FIG. 1 , the ten recording surfaces are numbered sequentially using two decimal digits (00 to 19) starting from the bottom surface of the top recording disk.
2.4.3 Cylinder address
GB 2950-82
All tracks with alternating track numbers in a disk group constitute a cylinder. The cylinder address is the track number. 2.4 .4 Track address
A track address is represented by a decimal number, where the high-order three digits determine the cylinder address, and the remaining two digits determine the recording surface address (the recording surface address is the recording mark number). 2.5 Index
Index! It is the point that determines the start and end of the track. At the moment when the leading edge of the index notch of the index disk is detected, the index is at the head (A head and B head, see Figure 3) Right below the read-write gap. At this time, the angle between the center line of the access path and the radius through the front edge of the index notch (see Figure 3) should be # = 42'g°
Center of the path
B head Read and write
Sewing storage line
A head number
Sewing access line
Index gap
Disk core||tt ||Figure 3 Index disk (top view)
2.6 Test area
2.6.1 Title area
For testing, the title is specified as: When the disk group rotates at 2400rpm, The x domain starts no later than 100us after the index and ends no earlier than 700μs after the index.
2.6.2 Data Area
For testing purposes, the data area is defined as: when the disk group speed is 2400rpm, it starts no later than 700μs after the index and continues to the next index.
3 Test conditions and disk loading
3.1 General conditions
3.1.1 Rotation speed
During any test, the disk group rotation speed should be 2400±24rpm, and the rotation direction should be 3.1.2 Air flow
The air flow (under standard conditions) should be 0.026 to 0.0014 m*/s, and the air pressure entering the disk group should not exceed 0.5 mbar. 3.1.3 Temperature
The air temperature entering the disk group should be 27±1℃. 3.1.4 Relative humidity
GB 2950—82
Relative humidity of air entering the panel should be 40% to 60%. 3.1.5 Adaptation time
Before testing, the panel It should be conditioned for 24 hours in the same environment as the test device. 3.2 Standard Reference Surfaces
There are two standard reference surfaces (standard amplitude reference surface and standard data reference surface), which are used to calibrate all two The standard reference surface is maintained in a designated institution. 3.2.1 Standard amplitude reference surface
8.2.1.1 Characteristics
The standard amplitude reference surface is characterized by the area indicated by the notches, and This area is defined as the period from 50μs to 275μs after the notch edge. When recorded at 1f frequency (see 3.4.3) without tunnel erasure and read using an amplitude test head (see 3.3.1), the reference surface should give the following input voltage:
at radius 115.087 At ±0.254mm, the peak-to-peak value is 7.0mV. At the radius of 166.7260.254mm, the peak-to-peak value is 11.5mV. 3.2.1.2 Secondary standard amplitude reference plane
Output voltage of the secondary standard amplitude reference plane It is related to the output voltage of the standard amplitude reference plane, and the relationship is expressed by the correction coefficient CAD. The correction coefficient CAn is:
Standard amplitude reference plane output voltage
Secondary standard amplitude reference plane output voltage
When tested in the area specified in 3.2.1.1, the qualified first-level standard The correction coefficient CAD of the amplitude reference plane should satisfy 0.90≤CAD1.10,
3.2.2 Standard data reference plane
3.2.2.1 Characteristics
The standard data reference plane is characterized by the area indicated by the notch, and the area is defined as the period from 50us to 275us after the notch edge. After straddling erase, when reading using the data test head (see 3.3.2), at a radius of 115.087±0.254mm, the reference plane should give the following output voltage:
If recorded at a 2f frequency (see 3.4.3), the peak-to-peak value is 4.0mV. If recorded at a 4f frequency (see 3.4.3), the peak-to-peak value is 2.0mV. 3.2.2.2 Secondary standard data reference plane
The output voltage of the secondary standard data reference plane is related to the output voltage of the standard data reference plane, and its relationship is expressed by the correction coefficient C (2f frequency is CDD2, 4f frequency is CDD4). The correction coefficient Cnn is:
Standard data reference plane output voltage
Secondary standard data reference plane output voltage
When tested in the area specified in 3.2.2.1, the correction coefficient CnD of the qualified secondary standard data reference plane should meet 0.90≤CDDr1.10g
8.3 Test head
3.3.1 Amplitude test head
A suitable amplitude test head should be used for amplitude test*. The correction coefficient CAH of the qualified amplitude test head should meet 0.90≤CAb≤1.10.
The correction coefficient CA is:
Standard amplitude reference plane output voltage
(actually measured magnetic output voltage)×CAD
*1SO The 1BM2316 (2311 type) amplitude test head in the example is a suitable head. GB2950—82
Wherein, the measured output voltage of the magnetic head is measured at two radii on the secondary standard amplitude reference plane (see 3.2.1.2) at a frequency of 1f.
3.3.2 Data test head
Other tests other than amplitude test shall use a suitable data test head*. The correction coefficient CDH of a qualified data test head shall satisfy 0,90≤CDH≤1.10.
The correction coefficient CDH is:
Standard data reference plane output voltage
(measured head output voltage)×CDn2Wherein, the measured output voltage of the magnetic head is measured at a radius of 115.087mm on the secondary standard data reference plane (see 3.2.2.2) at a frequency of 2f.
3.3. 2. 1 Resolution
The resolution of the data test head is tested in the same 225μs sector at a radius of 115.087mm on the standard data reference surface and is determined by the ratio of the average value of the 4f frequency to the 2f frequency read amplitude. The resolution of the data test head should be 40% to 60%. 3.8.2.2 Resonant frequency
When measured at the head lead plug, the resonant frequency of each read/write coil should be not less than 4.2MHz. 3.4 Special conditions
3.4.1 Measurement conditions for test heads
3. 4,1.1 Write current
The waveform of the write current with a frequency of 1" measured at the head lead plug is shown in Figure 4. Among them, the write current Iw:
Iwi+Iw2
=35±1mA.
The overshoot is equal to (5%~10%) 1w.
The difference between the positive and negative amplitudes of the write current [W should be
[Iw -Iw2<1mA,
TR =140~200ns,
Tr = 140 ~ 200s
ITR -TF I 20ns.
The difference between two adjacent half cycles T1 and T2 should not be greater than 2 %. Single
3.4.1.2 DC erase current
Figure 4 Write current waveform
*TSO's BM2316 (2314 type) data test head is a suitable head. %
GB 2950—82
When using DC erase, the DC erase current through one of the head read/write coils should be, IE = 35 1 1 mA.
3.4.1.3 Readout circuit
The differential input impedance of the readout circuit measured at the head lead plug should be the parallel connection of 7.5±0.37kg resistor and 45+5pF capacitor (including distributed capacitor and 4-collector capacitor) (see Figure 5). The flatness of the amplifier passband should not exceed 5% within 0.1~2.0.MHz. 3.4.2 Measurement conditions of data test head
3.4.2.1 Write current
The write current waveform of 2f frequency measured at the head lead plug is shown in Figure 4. Where I:
Iw++Iw2
=35±1mA (000~127 channels)
Iw = 30 ± 1 mA (128~202 channels). The overshoot is less than or equal to 8%Iw.
The difference between the positive and negative amplitudes of the write current 1w should be: [Iwi -IW? | .1mA.
TH = 120 - 160ns;
TF = 120 ~ 160 n5 #
I TR - TE20ns.
The difference between two adjacent half cycles T1 and T? should not be greater than 2%. 3.4.2.2 DC erase current
When using DC erase, the DC erase current through one of the head read/write coils should be: I ^ = 35 ± 1 mA( 000 ~ 127); Iz = 30 ± 1mA (128 ~ 202).
3.4.2.3 Readout circuit
The differential input impedance of the readout circuit measured at the head lead plug should be the parallel connection of 4.20 ± 0.21ks2 anode and 30 ± 5pF capacitor (including distributed capacitance and concentrated capacitance) (see Figure 5). Readout circuit
Figure 5 Readout circuit
The differential amplifier
under the input impedance of 100 k s2
The readout circuit should be able to receive a low impedance signal level of 0.6 ~ 10.0mV peak-to-peak. When the frequency is 0.5 ~ 3.0MHz, its linearity should be within 3% or 0.050mV (the larger value). 3.4.3 Test Signals
Specify 1f, 2f and 4f frequencies as
1f = (1250 ± 1.25) × 103 flips/second 2f = (2500 ± 2.50) × 10 flips/second 4f = (5000 ± 5.00) × 10° turns/second. 8.4.4 DC Edge Erase
Unless otherwise specified, all recording surface tests and track quality tests shall be edge erased. When using tunnel erase (TE) amplitude test heads, the edge erase current shall be: ITE = 40 + 2 mA.
When using straddle erase (SE) data test heads, the edge erase current shall be: IsE = 35 = mA.
3.4.6 Magnetic recording
GB 2950--82
Unless otherwise specified, a DC erase operation shall be performed before all write operations (see 3.4.1.2 and 3.4.2.2). 3. 4.6 Track position
During the track quality test (see 4.2), the track position is also required to be in accordance with 2.3, and the deviation from the nominal position shall not exceed 0.025mm. 3.4.7 Head loading force
The net loading force of the head at the loading point or equivalent loading shall be 3.43±0.10N. 4 Functional test
4.1 Recording surface test
4.1.1 Amplitude test
4.1.1.1 Step
Use the amplitude test head to write and read at 1f on any part of the recording surface. 4.1.1.2 Results
In the 50μs sector with the largest amplitude, the average peak-to-peak value of the read amplitude after calibration (see 3.3.1) shall be limited to the following range: the maximum amplitude is 9.3mV at a radius of 115.087mm, and then increases proportionally with the radius to 15.1mV at a radius of 166.726mm, but shall not exceed this value.
The minimum amplitude is 6.3mV at a radius of 115.087mm, and then increases proportionally with the radius to 10.0mV at a radius of 166.726mm, but shall not be lower than this value.
4.1.2 Resolution Test
4.1,2.1 Procedure
Write and read with a data test head at 2f on any part of the recording surface, then write and read at 4f at the same location after DC erasing.
4.1.2.2 Result
In any case, the ratio within the same 0μs sector, that is, the average value of the read voltage at 4f
and the average value of the read voltage at 2f
should be 0.55 ±0.20.
4. 1.3 Rewrite test
4.1.3.1 Steps
Write at 2f on track 000, and measure the average amplitude of the 2f signal with a frequency-selective voltmeter. Do not perform DC erasing, then rewrite at 4f, and measure the average amplitude of the 2f signal with a frequency-selective voltmeter. The magnetic head used should be a qualified heavy-duty magnetic head (see 4.1.3.3). 4.1.3.2 Overwrite residual degree
The overwrite residual degree is defined as:
The half-mean amplitude of the 2f signal measured after overwriting at 4f-×100%
The average amplitude of the 2f signal measured before overwriting at 414.1.3.3 Qualified overwrite head
Use the data test head to write and rewrite on the standard data reference surface. When the overwrite residual degree r is between 3% and 5%, the data test head can be used as a qualified overwrite head. 4.1.3.4 Result
The ratio of the overwrite residual degree of the measured recording surface to the overwrite residual degree of the data reference surface should not be greater than 1.3.4. 1.4 Positive modulation test
4.1.4. 1 Steps
Use the data test head to write a track at 2f and read it out. 4.1.4.2 Results
GB 2950-82
The average base-to-peak value measured in the 50μS sector with the largest amplitude on the track should be less than 146% of the average base-to-peak value of the entire track. 4.1.5 Negative modulation test
4.1.8.1 Steps
Write a track with 2f using a data test head and read it out. 4.1.5.2 Results
The average base-to-peak value measured in the 50μS sector with the smallest amplitude on the track should be greater than 75% of the average base-to-peak value of the entire track. 4.2 Track quality test
All tracks should be tested for quality using a data test head. The two test methods are described below. Method A is based on a fixed voltage reference. Method B is based on a track relative voltage reference. The method to be used can be agreed upon by both parties.
4. 2. 1 Hysteresis Pulse Test
4.2.1.1 Method A
Steps, write and read at 2f on each track. Result: Any read pulse whose base-to-peak value is less than 25% of the peak-to-peak value (see 3.2.2.1) of the standard data reference plane at 2f is a leakage pulse. The base-to-peak value is the value that appears between 150 and 250μs after the analog signal passes through zero. 4. 2.1.2 Method B
Steps: Write and read at 2f on each track. Result: Any read pulse whose base-to-peak value is less than 60% of the average base-to-peak value in the previous 50μs sector is a leakage pulse. 4. 2. 2 Pulse Test
4.2.2.1 Method A
Steps: Write and read at 2T on each track, then perform DC erase and read the residual pulse amplitude as specified in 3.4.2.2. Result: Any read residual pulse whose amplitude is greater than 2f of the track being tested 40% of the average base-to-peak value is a spike. The maximum base-to-peak value of any read residual pulse should not exceed 22.5% of the peak-to-peak value output of the standard data reference plane at 2f (see 3.2.2.1).
4.2.2.2 Method B
Steps, write at 2f on each track, read and record the average peak-to-peak value of the 50μs sector with the largest track signal, called V, then perform DC erase and read the residual pulse amplitude according to the provisions of 3.4.2.2. Result: Any read residual pulse whose base-to-peak value exceeds 25% of 1/2Vs is a spike. 4.2.8 Ease of use test
4.2.8.1 Method A
Steps: Write and read at 2f on each track. Perform DC erase as specified in 3.4.2.2, then read the residual signal amplitude. Result: The average peak-to-peak value of the residual signal measured in any 50μs sector on the erased track shall not exceed 4% of the maximum average peak-to-peak value of the 2f signal in the 50us sector of the track (the measurement of the residual signal is independent of the noise of the test system). The maximum peak-to-peak value of the residual signal shall not exceed 10% of the 2f output of the standard data reference plane (see 3.2.2.1). 4.2.3.2 Method B
Steps: Write at 2f on each track, read and record the average peak-to-peak value of the 50us sector with the largest track signal, called VA. Perform DC erase as specified in 3.4.2.2, and then read the residual signal amplitude. Result: The average level of the 50μs sector with the largest read signal should not exceed 10% of 4. 4. Qualification criteria
4.8.1 Recording surface inspection criteria
Qualified disk groups should meet all recording surface test requirements specified in 4.1. Table. 8.2 Magnetic avoidance quality inspection criteria
4.8.2.1 Defects
GB 2850-82
Any failure to meet any of the requirements specified in 4.2 is considered a defect. Per .3.2.2 Defect-free requirements
There should be no defects in the medullary area (see 2.6.1) of any track and the track with address 0000. In order to achieve data interchange, a qualified disk group should have at least 4000 defect-free tracks.1 Method A
Procedure: Write at 2f on each track and read out. Perform DC erase as specified in 3.4.2.2, and then read the residual signal amplitude. Result: The average peak-to-peak value of the residual signal measured in any 50μs sector on the erased track shall not exceed 4% of the maximum average peak-to-peak value of the 2f signal in the 50us sector of the track (the measurement of the residual signal is independent of the noise of the test system). The maximum peak-to-peak value of the residual signal shall not exceed 10% of the 2f output of the standard data reference plane (see 3.2.2.1). 4.2.3.2 Method B
Procedure: Write at 2f on each track, read out and record the average peak-to-peak value of the 50us sector with the largest track signal, called VA. Perform DC erase as specified in 3.4.2.2, and then read the residual signal amplitude. Result: The average level of the 50μs sector with the largest read signal shall not exceed 10% of 4. 4.Qualification criteria
4.8.1 Recording surface inspection criteria
Qualified disk groups shall meet all the recording surface test requirements specified in 4.1. Table.8.2 Magnetic avoidance quality inspection criteria
4.8.2.1 Defects
GB 2850-82
Anything that does not meet any of the requirements specified in 4.2 is considered a defect. Each.3.2.2 Defect-free requirements
There should be no defects in the medullary area (see 2.6.1) of any track and the track with address 0000. In order to achieve data interchange, a qualified disk group should have at least 4000 defect-free tracks.1 Method A
Procedure: Write at 2f on each track and read out. Perform DC erase as specified in 3.4.2.2, and then read the residual signal amplitude. Result: The average peak-to-peak value of the residual signal measured in any 50μs sector on the erased track shall not exceed 4% of the maximum average peak-to-peak value of the 2f signal in the 50us sector of the track (the measurement of the residual signal is independent of the noise of the test system). The maximum peak-to-peak value of the residual signal shall not exceed 10% of the 2f output of the standard data reference plane (see 3.2.2.1). 4.2.3.2 Method B
Procedure: Write at 2f on each track, read out and record the average peak-to-peak value of the 50us sector with the largest track signal, called VA. Perform DC erase as specified in 3.4.2.2, and then read the residual signal amplitude. Result: The average level of the 50μs sector with the largest read signal shall not exceed 10% of 4. 4.Qualification criteria
4.8.1 Recording surface inspection criteria
Qualified disk groups shall meet all the recording surface test requirements specified in 4.1. Table.8.2 Magnetic avoidance quality inspection criteria
4.8.2.1 Defects
GB 2850-82
Anything that does not meet any of the requirements specified in 4.2 is considered a defect. Each.3.2.2 Defect-free requirements
There should be no defects in the medullary area (see 2.6.1) of any track and the track with address 0000. In order to achieve data interchange, a qualified disk group should have at least 4000 defect-free tracks.
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