Abstract:
A method and apparatus for storing entries in at least two separate storage areas of a non-volatile memory in a communications terminal, wherein the storage areas have fixed area boundaries, such that a dynamic redial list in the communications terminal is increased in a highly cost-effective fashion.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a method and apparatus for storing entries in at least two separate storage areas of a non-volatile memory and, in particular, to a dynamic redial list in a telecommunications terminal. 
     2. Description of the Prior Art 
     Conventional telecommunications terminals such as, for example, cordless telephones or mobile phones have a non-volatile memory for storing telephone entries, but such non-volatile memory has only a limited capacity. 
     FIG. 4 shows a schematic view of such a non-volatile memory  1  in which, for example, a permanently predefined storage area A is provided for a telephone directory list, a permanently predefined storage area B is provided for a redial list and a permanently predefined storage area C is provided for customer-specific settings such as volume, ringing tone, warning tones, language etc. The storage area A for the telephone directory list usually has a size of approximately 100 entries (name and call number). The storage area B for the redial list is usually significantly smaller than the storage area A for the telephone directory list and has a capacity of approximately 5 to 10 entries (call numbers). The storage area C is reserved in the non-volatile memory  1  for what are referred to as customer-specific settings, and cannot be used for telephone entries. 
     However, such a conventional way of implementing telephone entries in a non-volatile memory  1  has the disadvantage that, in particular, the list for the redials, i.e. the storage area B, is too small. In addition, the use of a non-volatile memory with a relatively high storage capacity cannot be considered for cost reasons. 
     JP 06119234 discloses an arrangement for the administration of storage in which data from a central processor unit is stored in a memory, this data passing through a distinguishing unit which stores the data in a first area of the memory if the data is data which is not to be deleted, and in a second data area if it is data which is to be deleted when an update is made. If the memory space requirement of the data which is to be stored in the first area exceeds the capacity of the first area, the data which is in excess of the capacity of the first area is copied into the second area, and this part of the second area is added to the first area, while the rest of the second area is subjected to what is referred to as “garbage collection”, i.e. an update is performed in which the data of the second area is deleted, after which the free area of the memory which is created is divided into a new first area and a new second area. 
     The present invention is, therefore, directed to providing a method and apparatus for storing telephone entries in which particularly the redial list is increased in a cost-effective fashion. 
     SUMMARY OF THE INVENTION 
     According to the present invention, by sensing free memory space in one of the separate storage areas and assigning weightings for the various storage areas it is possible to dynamically distribute the entire storage areas of the non-volatile memory, resulting in an optimum utilization of the expensive non-volatile memory. 
     Separate storage areas preferably contain a higher ranking telephone directory list and a lower ranking redial list. Given additional evaluation of the weightings for separate storage areas, up to 100 redial call numbers can thus be stored dynamically at the start of the redial list, its storage capacity being gradually reduced as the higher ranking telephone directory list is filled up. The storage capacity of the non-volatile memory is thus completely used from the start. 
     In order to prevent the redial list from being completely expelled from the memory, there is preferably the possibility of reserving a minimum size for the redial list which has an identical weighting to the telephone directory list and which, therefore, cannot be deleted. 
     As a result, when the telephone directory list is completely utilized, a minimum number of call numbers in the redial list is ensured. 
     Additional features and advantages of the present invention are described in, and will be apparent from, the following Detailed Description of the Preferred Embodiments and the Drawings. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a schematic view of a non-volatile memory before and after the storage of an entry; 
     FIG. 2 shows a flowchart representing the method steps in accordance with a first exemplary embodiment of the present invention; 
     FIG. 3 shows a flowchart representing the method steps according to a second exemplary embodiment of the present invention; and 
     FIG. 4 shows a schematic view of a non-volatile memory with a fixed memory partition according to the prior art. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 shows a schematic view of a non-volatile memory  1  before and after the storage of entries in a storage area A. 
     Identical reference symbols designate identical components to those in the non-volatile memory  1  according to FIG. 4, for which reason a detailed description is not given here. The non-volatile memory  1  according to FIG. 1 is composed, before the storage of entries in a telephone directory list, of a separate storage area A, a separate storage area B min , a separate storage area B rem  and a separate storage area C. The storage area C is used for storing customer-specific settings, as in the prior art according to FIG.  4 . Such settings may be, for example, the volume, the ringing tone, warning tones, the language etc. of a communications terminal. The non-volatile memory  1  is composed, for example, of an EEPROM or FLASHROM, and is located in a cordless telephone or mobile phone. However, it can also be used in a wire-bound telephone or some other telecommunications terminal in which there is just a limited storage capacity for telephone entries. 
     The storage area A stores, for example, a telephone directory list in the form of names and associated call numbers, as in the prior art. The reference B designates a separate storage area for storing a redial list and is composed, for example, of a minimum redial list B min  and a remaining redial list B rem . The reference SP designates a virtual global memory which is available for storing telephone entries. The storage capacity of the virtual global memory SP is made up, according to FIG. 1, of the difference between the overall capacity of the non-volatile memory  1  and the capacity for the customer-specific settings in the storage area C. 
     In contrast to the prior art in which there is a fixed assignment of the storage areas A, B and C, in the present invention the virtual global memory SP is dynamically partitioned. 
     To be more precise, a non-volatile memory  1  has, at the start of its programming, a relatively low number of telephone directory entries in the storage area A. However, because the telephone is already intensively used, whenever a telephone call is made, call numbers are stored in the redial list B, which can use the remaining memory space of the virtual global memory SP owing to dynamic distribution. This provides the advantage that the free memory space in the telephone directory list A is not lost owing to a fixed assignment as in the prior art. 
     Given intensive use of the communications terminal, entries are increasingly stored in the telephone directory list A. The storage area A for the telephone directory list has here a higher weighting than the storage area B of the redial list. Owing to this fact, when a new entry E is present for the telephone directory list A, the oldest entries E in the redial list of the storage area B are automatically deleted and used as storage area A for the new telephone directory entry E. In this way, the storage area A grows, during which process there is a dynamic shifting of the partition between the storage areas A and B. 
     In order to avoid the storage area B for the redial list being completely expelled, part of the redial list B min  can be assigned an identical weighting to the storage area A for the telephone directory list. In this case, a storage area B is pushed back only to a storage area B min  of the storage area A for the telephone directory list, as a result of which a minimum number of redials in the storage area B min  is also kept available for complete utilization of the telephone directory list. This state is represented on the right-hand side in FIG. 1 in which the non-volatile memory  1  or its virtual global memory SP is completely filled with entries E for the telephone directory list with the exception of the minimum redial list in the storage area B min . 
     The method for the dynamic partitioning of the virtual global memory SP described above will be described below in detail. 
     FIG. 2 shows a flowchart of the method steps according to a first exemplary embodiment of the present invention. 
     The reference SI designates an initialization phase for the method according to the present invention. In a step S 2 , the predetermined weightings which indicate a certain hierarchy for the occupation or expansion of memory spaces in the non-volatile memory  1  are assigned to the separate storage areas A, B min  and B rem  of the non-volatile memory  1 . A storage area A for a first list has, for example, a higher weighting than a storage area B rem  for a second list. 
     In a step S 3 , a current entry E is input for a predetermined storage area. This can be, for example, an entry E for a first list, composed of name and call number, or merely a selected call number which is to be stored in the second list. In order to sense a remaining free memory space in the non-volatile memory  1 , it is possible, for example in a step S 4 , for the separate storage areas A, B min  and B rem  to be combined to form a virtual global memory SP. 
     In an interrogation step S 5 , a check is made to determine whether free memory spaces are still present in the virtual global memory SP. If the result of the check in step S 5  is positive, i.e. there is sufficient space for a current entry E in the virtual global memory SP, the method proceeds to a step S 9 . In step  9 , the current entry E for the predetermined storage area is stored. To be more precise, an entry E for the first list is stored in the storage area A, while a current entry E for the second list is stored in the storage area B. 
     If the result of the check in step S 5  is negative, i.e. there is still no space or not sufficient space free for a complete current entry E in the virtual global memory SP, the method proceeds to a step S 6 . In step S 6 , it is checked whether there are storage areas with a lower weighting than the predetermined storage area of the current entry E. In the event that the entry E for the first list is to be input, i.e. in the storage area A, the storage area B rem  has a lower weighting than the storage area A. Accordingly, there is a storage area with a lower weighting and the method proceeds to a step S 8 . 
     In step S 8 , the entries in the storage area B rem  with a lower weighting are deleted. To be more precise, in step S 8  entries are deleted in the storage area B rem  with a lower weighting until there is sufficient space for the current entry E which is to be stored. After this deletion process in step S 8 , the storage of the current entry E takes place, in turn, for its predetermined storage area in step S 9 . To be more precise, after the deletion of entries from the second list B rem  an entry would be stored in the first list; i.e., in the storage area A. The storage area A for the first list has thus expanded dynamically in the virtual global memory SP. 
     If, on the other hand, it is detected in step S 6  that there are no further storage areas with a lower weighting, the method ends the storage procedure in a step S 7  with the message “memory full”. This case occurs, for example, if the same weighting has been assigned to a storage area B min  for a third list as to the first list A. In this case, there is no further storage area with a lower weighting, for which reason the method refuses a further entry for the first list in the storage area A with the message “memory full”. 
     FIG. 3 shows a flowchart of the method according to the present invention in accordance with a preferred second exemplary embodiment. The second exemplary embodiment is configured in particular for the use of a telephone directory list and a redial list in a communications terminal. 
     In a step S 10 , an initialization phase for the method takes place. In a step S 11 , a current entry E for a predetermined storage area or a desired list is input in turn. 
     In an interrogation step S 12 , it is checked whether or not the entry E is to be entered in the storage area A for the telephone directory list. In the event that the entry E is not to be entered in the telephone directory list A, the method proceeds to a step S 13  in which it is checked whether a memory space in a storage area B for a redial list is sufficiently large for the current entry E. In the event of the free memory space in the storage area B being sufficiently large for the redial list, the current entry E is subsequently stored in the storage area B in a step S 15 . If, on the other hand, the memory space in the storage area B is not sufficiently large for the current entry E, the oldest entry in the storage area B is deleted in a step S 14  and the current entry E is stored. This deletion process or storage process corresponds here to the storage process in a stack memory which is arranged in a torus. To be more precise, the oldest entries are overwritten in each case with the current entries if the storage area B is already filled. Reading out takes place in this storage area in the reverse order, i.e. LIFO (last in first out), the last entry being read out first. 
     If, on the other hand, the current entry E in step S 12  is a telephone directory entry, i.e. the current entry E is to be entered in the storage area A, an interrogation step S 16  is then carried out. 
     In step S 16  it is checked whether the memory space in the separate storage area A is sufficiently large for a maximum entry E max . This ensures that the current entry E can be stored completely in the separate storage area A for the telephone directory list. If it is detected in step S 16  that there is sufficient memory space available in the separate storage area A for the telephone directory list, the current entry E is then stored in a step S 21  in the separate storage area A. If, on the other hand, there is not sufficient memory space present in the separate storage area A, the method is continued with a step S 17  in which it is checked whether a minimum size B min  of the separate storage area B for the redial list has already been reached. If this is the case, the method ends in a step S 19  with a message “memory full”. In this case, no further entry can be made in the telephone directory list because both the storage area A and the storage area B min  are completely written to. 
     If, on the other hand, the result in step S 17  is negative, i.e. the minimum size B min  of the separate storage area B for the redial list has not yet been reached, a further check is carried out in a step S 18 . To be more precise, in step S 18  it is checked whether the minimum size B min  of the storage area B has been reached if a memory space for a maximum entry E max  has been deleted from the separate storage area B. This interrogation ensures, in step S 18 , that the “memory full” message is output in step S 19  even if the minimum size B min  of the separate storage area B for the redial list has not yet been reached in step S 17 , but the current entry E is of such a size that a necessary deletion process of the entries in the separate storage area B would be less than the minimum size B min . However, if the result in step S 18  is negative, i.e. the minimum size B min  of the separate storage area B is not reached even if a corresponding memory space for a maximum entry E max  is deleted, the method proceeds to a step S 20 . 
     In step S 20 , the oldest entries in the separate storage area B for the redial list are deleted, as a result of which free memory space is generated. The generated free memory space is then assigned or redistributed to the separate storage area A for the telephone directory list. In the following step S 21 , the current entry E is then stored in the separate storage area A for the telephone directory list. 
     The apparatus device for implementing the method described above, i.e. for storing telephone entries in at least two separate storage areas of a non-volatile memory, is preferably composed of an input unit, which corresponds to the conventional keypad of a telephone or communications terminal. The other units, for example an assignment unit for assigning weightings, a first sensing unit for sensing free memory space and a second sensing unit for sensing storage areas with a low weighting, are preferably implemented in a central processor unit (CPU) of a communications terminal and are not described below in more detail. The non-volatile memory  1  is preferably composed of an EEPROM or FLASHROM and constitutes a permanent-storage data memory. The present invention is preferably implemented in a cordless telephone or a mobile phone because there is a particular need for telephone directory lists and redial lists in these communications terminals. 
     The present invention has been described above with reference to telephone directory lists and redial lists. However, it is not restricted thereto and can also administer, for example, lists for abbreviated dialing numbers. In this way, even the storage area C for customer-specific settings also may be dealt with. In addition, the method according to the present invention and the associated device can also be operated in a wire-bound telecommunications terminal, such as a video phone, or in a computer-controlled terminal. 
     Indeed, although the present invention has been described with reference to specific embodiments, those of skill in the art will recognize the changes may be made thereto without departing from the spirit and scope of the invention as set forth in the hereafter appended claims.