Analysis of test 1

It is known that each Chinese character is represented by a lattice of 16× 16, that is, the capacity of each Chinese character is 16× 16/8=32B, and the font capacity of 7500 Chinese characters is 32b× 7500 = 240000b = 234.375kb..

Test 2 analysis

The principle of magnetic surface storage is as follows:

(1) recording medium: In magnetic surface memory, information is recorded on the surface of a thin layer of magnetic material, and this layer of material and attached carrier are called recording medium or recording medium. Carriers are made of nonmagnetic materials and can be divided into soft carriers and hard carriers according to their properties.

(2) magnetic head: the magnetic head is one of the key components of magnetic recording equipment, and it is an electromagnetic conversion element, which can convert the binary code represented by electric pulse into the magnetization state on the magnetic recording medium, that is, electromagnetic conversion; On the contrary, the magnetization state on the magnetic recording medium can be converted into electric pulses, that is, magnetoelectric conversion.

The reading and writing principle of magnetic surface memory is as follows.

In the process of reading and writing, the relative motion between the recording medium and the magnetic head is generally that the recording medium moves while the magnetic head does not move.

(1) writing process: write current in a certain direction is applied to the coil of the writing head, so that the local area under the head is magnetized to form a magnetized unit or a recording unit. When this part of the medium moves out of the active area of the magnetic head, it will still leave a strong enough remanence. When positive and negative currents are written in the writing head, two different remanence states will be generated, which just correspond to "1" and "0" of binary information.

(2) Reading process: When reading, no current is applied to the reading coil. When the magnetizing unit moves under the reading head, the magnetic flux flowing in the reading head changes greatly, so the induced electromotive force E is generated at both ends of the reading coil. After the induced electromotive force E is amplified, detected, limited and shaped, the signal that meets the requirements is obtained.

Test 3 analysis

As shown in Figure 4-2, right-click the Recycle Bin, and the menu items displayed in the shortcut menu include Open, Resource Manager, Empty Recycle Bin, Create Shortcut and Properties. The command that won't appear is to restore files.