This standard makes necessary provisions for the magnetic properties of top-loading single-disc interchangeable disk cartridges in order to ensure their interchangeability. All general and mechanical properties of disk cartridges shall comply with the provisions of GB 2308-80 "Mechanical properties of top-loading single-disc interchangeable disk cartridges". This standard applies to disk cartridges used in data processing systems. GB/T 2948-1982 Magnetic properties of top-loading single-disc interchangeable disk cartridges GB/T2948-1982 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Magnetic characteristics of jnterchangeablemagnetic single disk cartridge (top loaded) UDC 681.327.63
GB 2948 —82
This standard makes necessary provisions for the magnetic properties of top-loaded single-disc replaceable cartridge disks (hereinafter referred to as cartridge disks) so as to ensure their replaceability. All general and mechanical properties of cartridge disks shall comply with the provisions of GB2308-80 "Mechanical properties of top-loaded single-disc replaceable cartridge disks". This standard applies to cartridge disks used in data processing systems. This standard is formulated with reference to the magnetic properties part of the International Organization for Standardization standard ISO3562-1976 (E) "Information Processing - Mechanical Properties and Magnetic Properties". Configuration of recording surface and magnetic head
The configuration of the recording surface and magnetic head is shown in Figure 1 and the table below. Fuel line merchant
Account access frequency
Energy transfer center
Figure 1 Geometry of head-disk system
Configuration of head and recording surface
No. (head or recording surface)
Note: "D" in the table means the floating surface of the head is downward, and "U" means the floating surface of the head is upward. Issued by the General Administration of Standards of the People's Republic of China on March 29, 1982
Single-disc interchangeable cartridge disk (top loading
Head direction
Implementation on January 1, 1983
2 Track geometry parameters
2.1 Number of tracks
GB 2948-82
Each recording surface should have 204 concentric circular tracks of different radii. 2.2 Track width
After straddling erasure, the track width of the disk with 1 record should be 0.175-0.025mm. The area between the tracks should be erased. A method for measuring the effective track width is recommended in Appendix A. 2.3 Track position
2.3.1 Nominal position
The geometric signature of the head-disk system is shown in Figure 1. The nominal value of the track centerline radius can be calculated by the following formula at 23°C: Rn =R73 - (n-73)× S
Where: Radius of track 73 centerline:
R73 - 148.175mm.
Head displacement increment:
S=0.254mm.
Track number:
n=0~203.
2.3.2 Track position tolerance
At 23℃, the deviation of the measured position of the recorded track centerline from the nominal position should be within ±0.025mm. Note: ①) Since track 73 is used to calibrate the drive, the deviation of the track 73 position should be within ±0.0075mm. ②At other temperatures (within the range specified in GB230H-80), the nominal position of the track centerline can be calculated using the linear expansion coefficient 24×10-/C.
2.3.3 Recording deflection angle
At the moment of screening or reading H, the maximum deflection angle between the magnetization reversal and the head access line can be 130°. 2.4 Marks
Use the following marks for testing.
2.4.1 Track Marks
Track marks are indicated by two-digit decimal numbers (000~203). Each recording surface is numbered sequentially from the outermost track to the inside. 2.4.2 Recording Surface Marks
Use the number 0 to indicate the upper recording surface and the number 1 to indicate the lower recording surface. 2.4.3 Cylinder Address
Tracks with the same track mark number are grouped into a cylinder. The cylinder address is the track mark number. 2.4.4 Track address
A track address is represented by a four-digit decimal number, the three high-order digits determine the surface address, and the remaining digit determines the recording surface address (the recording surface address is the recording surface mark number). 2.5 Index
The index 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 armature plate is detected, the index is directly below the head read gap on the access line. At this time, the access line and the leading edge of the index notch form an angle α (see Figure 2), and its nominal value is 18U°. 2.6 Test Area
2.6.1 Header Area
GB 2948—82bZxz.net
Practical Version
History Version
Figure 2 Track Index (Top View)
For testing purposes, the header area is defined as: when the disk speed is 2400rpm, it starts no later than 120μs after the index and ends no earlier than 370μs after the index.
2.6.2 Data Area
For testing purposes, the data area is defined as: when the disk speed is 2400rpm, it starts no later than 370μs after the index and continues to the area between the next index.
3 Test Conditions and Equipment
3.1 General Conditions
3.1.1 Rotation Speed
During any test, the disk rotation speed shall be 2400±24rpm, and the rotation direction shall be counterclockwise (looking down). 3.1.2 Temperature
The temperature of the air entering the disk box shall be 27±1℃. 3.1.3 Relative Humidity
The relative humidity of the air entering the disk box shall be 40%~60%. 3.1.4 Acclimation Time
Before testing, the disk shall be acclimated to the same environment as the test equipment for 24 hours. 3.2 Standard Reference Surfaces
There are two standard reference surfaces (standard amplitude reference surface and standard data reference surface), which are used as the reference for calibrating all secondary standards. The standard reference surfaces are kept in the designated institution. 8.2.1 Standard Amplitude Reference Surface
3.2.1.1 Features
The standard amplitude reference surface is characterized by the area indicated by the notch, and the area is defined as the period from 50μs to 275us 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 output voltage:
GB 294B-82
At a radius of 115.087±0.254 nm, the peak-to-peak value is 7.0mV, and at a diameter of 166.72610.254mm, the peak-to-peak value is 11.5mV. 3.2.1.2 Secondary Standard Amplitude Reference Surface
The output voltage of the primary standard amplitude reference surface is related to the output voltage of the standard amplitude reference surface, and the relationship is expressed by the correction coefficient CAD. The correction coefficient CAD is:
Output voltage of standard amplitude reference plane
Output voltage of secondary standard amplitude reference plane
When tested in the area specified in 3.2.1.1, the correction coefficient CAD of the qualified secondary standard amplitude reference plane should meet 0.90CADs1.10.
3.2.2 Standard data reference plane
3.2.2.1 Characteristics
The standard data reference plane is indicated by the notch The area characterization is defined as the period from 50us to 275us after the edge of the notch. After the straddle erase, when the data test head (see 3.3.2) is used to read, at the radius 115.087 = 0.254mm, the reference surface should give the following output voltage:
If recorded at 2f frequency (see 3.4.3), the peak-to-peak value is 4.0mV, if recorded at 4F frequency (see 3.4.3), the peak-to-peak value is 2.0mV. 3.2.2.2 Secondary standard data reference surface
The output voltage of the secondary standard data reference surface is related to the output voltage of the standard data reference surface, and the relationship is expressed by the correction coefficient CDD (CoD2 for 2f frequency and Cu for 4f frequency). The correction coefficient CnD is:
Standard data reference plane output voltage
I. Level standard data reference plane output voltage
When tested in the area specified in 3.2.2.1, the correction coefficient CDm of the qualified first-level standard data reference plane should meet 0.90CnL1.10.
3.3 Test head
3.3.1 Amplitude test head
A suitable amplitude test head* should be used for amplitude testing. The correction coefficient CAH of the qualified amplitude test head should meet 0.90≤,C.4H1.10.
Correction coefficient CAH is:
Standard amplitude reference plane output voltage
(Measured head output voltage)×CAN
Wherein, the measured magnetic output voltage is measured at two radii on the level standard amplitude reference plane (see 3.2.1.2) at a frequency of 1f.
3.3. 2 Data test head
Other measurements other than amplitude test should use a suitable data test head**. The correction factor CDI of a qualified data test head should meet 0,H,Gm 1,10.
Correction coefficient CnH is:
Standard data reference surface output voltage
(measured head output voltage)×CDD2 Wherein, the measured head output voltage is obtained at a radius of 115.087mm on the secondary standard data reference surface (see 3.2.2.2) at a frequency of 2f.
, the IBM2316 (2311 type) test head given by ISO is a suitable head. **The IRM2316 (2314 type) data test head given by ISO is a suitable head. 8.3.2.1 Resolution
The resolution of the GB 2948-82
data test head is tested in the same 225us sector at a radius of 115.087mm on the standard data reference surface and is determined by the ratio of the average amplitude readout at the 41 frequency to the 2f frequency. The resolution of the data test head should be 40%~60%. 3.3.2.2 Resonant frequency
When measured at the head lead plug, the resonant frequency of each read/write line should be no less than 4.2MHz. 3.4 Special conditions
3.4.1 Measurement conditions for amplitude test heads 9.4.1,1 Write current
, the write current waveform of 1f frequency measured at the head lead plug is shown in Figure 3. Among them: write current W
IWI+Iw2
..=35+ImA.
Overshoot amount (5%~10%)IW.
The difference between the positive and negative degrees of the write current should be:
lWi=Iw2limA
TR = 140 ~200 ns
T'F = 140 ~ 200 ns
ITR- TF20as
The difference between two adjacent half cycles T1 and T2 should not be greater than 2%.
3.4.1.2 DC erase current
Write current waveform
When listening?
When using DC erasure, the DC erasure current through the head read/write coil should be: IE=33±1mA
3.4.1.3 Readout circuit
The differential input impedance of the readout circuit measured at the head lead should be a parallel connection of 7.5±U.37k resistors and 45±5pF capacitors (including distributed capacitors and concentrated capacitors) (see Figure 4). The flatness of the amplifier passband should not exceed 5% within 0.12.UMHz. Read
Figure 4 Readout circuit
Differential amplifier with input impedance greater than 100 k 0
3.4.2 Measurement conditions of data test head
3.4.2.1 Write current
GB 2948-—82
The write current waveform of 2f frequency measured at the head lead plug is shown in Figure 3. Among them: Iwi+Iw2=35±1mA(000~127 tracks)
/w=30±1mA(128~203 tracks)
The overshoot is less than or equal to 8%Iw.
The difference between the positive and negative amplitudes of the write current I should be: [IWi - IW2 |
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