JPS62167695A - Memory writing method - Google Patents

Abstract

PURPOSE:To decrease the access time by writing information of memory management sequentially from the minimum address (or maximum address) of a memory and writing data sequentially from the maximum address (or minimum address) of the memory. CONSTITUTION:A space S is written on the 1st word and when data to be written on first takes place, a file name is written at first on the 1st word and address data 'FFFF' is written on the 2nd word. Then the data is written sequentially from the address 'FFFF' on the smaller address and when the last data is written on the address 'FF00', the end address 'FF00' of the written data is written on the 3rd word and a space S is written on the 4th word. When the data to be written again takes place, a file name is written on the 4th word and the address data 'FFFF' less than the address 'FF00' by one is writing on the 5th word. The processing above is repeated. Thus, all the storage capacity of the memory is used effectively and the access time is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a memory writing method particularly suitable for use in writing to a small capacity memory.

"Prior Art" In recent years, all kinds of IC cards in the shape of a credit card have been developed. This IC card has a smaller storage capacity than a floppy disk, etc., so this
It is necessary to use α capacity more effectively and without waste. The present invention provides a memory writing method that allows memory capacity to be used without waste.

Conventionally, the following writing method has been used for floppy disks. That is, FIG. 2 is a diagram showing the entire storage area of a floppy disk, and this storage area is preliminarily divided into a directory area DI'tE, a file
It is divided into an allocation table area FTE and a data area DAE. The directory area DRE has an area Dr1-DrKh<1 in which the directory of, for example, Kf12J is written. Further, the data area DAE is divided into, for example, N data blocks 1) bl-DbN of equal capacity. Further, in the file allocation table area FTE, as shown in FIG. 3, areas Fal=FaN (8 bits each) are provided corresponding to each of the data blocks Dbl to DbN.

Then, in the directory area DRE, the file name (
For example, rA BCl, rD E I? 'J, etc.) and the number of the data block Db in which the first data of the file is stored (ro I JJO3J, etc.) are written. Further, the following data is written in each area F'al to FaN of the file allocation table area FTE. First, the corresponding data block D
If no data is written to b, the data “00
" is written. Next, for example, data block Db+
If the data continues to data block Db2, data "02" (next data block number) is written in area Pal.

For example, if the data of one file ends at data block Db4, data "80" is stored in area Fa4.
" is written.

The examples shown in FIGS. 2 and 3 show that data is written as follows. That is, the data of file rABcJ is first written to data block Dbl, then written to data block Db2, then written to data block Db4,
It ends with this data block Db4. The data of the file rD E F' J is first written to the data block Db3, and then the data of the file rD E F' J is written to the data block Db3.
b5 and ends with this data block I)b5.

Moreover, data blocks D b6 , D b7 , D b
No data is written to N.

Also, when writing new data, first scan the file allocation table area F'rE to detect an empty data block Db, then register the directory area DRE, and then register the detected data block. [Write data into knock Db. If the data block Db becomes r'ULL, the file allocation table area I" T
E is scanned to detect a free data block Db, and then the file application [J application table area F'TE
is written, and then the detected data block D
Write data in b, and repeat the above process. When all the data in the file has been written, data "80" is finally written in the file allocation table area FTE.

"Problems to be Solved by the Invention" By the way, in the conventional writing method described above, the data block Db to which the last data is written is usually
This does not result in a ULL state, resulting in wasted power (and also requires one area called the file allocation table area FTE that is not used for data writing. Also,
File allocation table area FTE
Since the memory is accessed via , there is a problem that the access time becomes long.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a memory writing method that can use memory capacity without wasting it and shorten access time.

"Means for Solving the Problem" This invention writes memory management information sequentially from the minimum address (or maximum address) of the memory, and writes data sequentially from the maximum address (or minimum address) of the memory. It is a feature.

Embodiment An embodiment of the memory writing method according to the present invention will be described below with reference to the drawings.

Reference numeral ME in FIG. 1(a) indicates the entire storage area of the memory in which data is written. This memory has a minimum address of rooooJ and a maximum address of rFI"r;'F
'j (hexadecimal number). Furthermore, writing/reading is performed in this memory in units of bytes. Furthermore, in the following explanation, it is assumed that a word consists of two bytes. Also, address ro O00JJO00N
2 bytes of 1st word, address r0002J, ro
The 2 bytes of OO3J are used as the second word, and will be referred to in the same manner from now on.

In the writing method according to this embodiment, first, before starting data writing, as shown in FIG.
Write a space S in Word. Next, when the first data to be written occurs, as shown in FIG. ). Next, address If;'r'FFJ
From there, data is written sequentially in the direction of small addresses. Assume now that the last data has been written to address rFFOOJ. Next, the end address rF of the written data
Write F”00J to the third word, and then write space S to the fourth word.Next, if data to be written again occurs, search for spaces S sequentially from the minimum address r0000J, and write 1 of the detected space S. The end address rFFOOJ is detected from the contents of the previous word.Next, as shown in Figure 1 (c), the file name is written in the fourth word where the space S has been written, and then the The address rFF detected in the process of
Address data rFEF'FJ, which is one smaller than OOJ, is written in the fifth word. Then its address rFEFF
Data is written sequentially from J toward smaller addresses.

Next, when data writing is completed, an end address (rFEOIJ) is written in the sixth word, and then a space S is written in the seventh word. Thereafter, the above process is repeated every time data to be written is generated.

According to the above writing method, the data block D to which the last data explained in FIG.
No waste occurs in b. Further, since the file allocation table area FTE shown in FIG. 2 is not required, the entire storage area of the memory can be used more effectively and the memory access time can be shortened.

Furthermore, when the writing shown in Figure 1 (b) is completed,
In the fourth word following the space S, the next starting address rF
You may also write EFFJ.

In this way, the start address can be easily detected when writing the next data.

Further, in the above embodiment, the file name is one word, but it goes without saying that a plurality of words may be assigned to the file name. Furthermore, in the above embodiment, memory management information is written sequentially from the smallest address and data is written sequentially from the largest address, but conversely, memory management information is written from the largest address and data is written from the smallest address. You may also write it.

"Effects of the Invention" As explained above, according to the present invention, memory management information is written sequentially from the minimum address (or maximum address) of the memory, and data is sequentially written from the maximum address (or minimum address) of the memory. Since writing is performed, the entire storage capacity of the memory can be used without waste, and the access time is also shorter than that of the conventional writing method.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining a memory writing method according to an embodiment of the present invention, FIG. 2 is a diagram showing a data writing state of a floppy disk, and FIG. 3 is a diagram showing the file allocation in FIG. 2. - It is a diagram showing the table area FTE. ME・・・・・・All storage areas of memory Figure 2

Claims (1)

[Claims] A memory writing method for writing data to a memory, characterized in that information for memory management is written sequentially from the minimum address (or maximum address) of the memory, and data is written sequentially from the maximum address (or minimum address) of the memory. Memory writing method.