Semiconductor storage device

Abstract

According to an embodiment, a semiconductor storage device includes a first storage unit, a read control unit, a second storage unit, and a write control unit. The first storage unit is configured to store data supplied from a host device. The read control unit is configured to perform control of reading the data in accordance with a read request. The second storage unit is configured to store a logical address used for reading the data from the first storage unit by the read control unit. The write control unit is configured to perform control of adding the stored logical address to the data and write the resulting data into the first storage unit in a case where a size of the data requested to be written into the first storage unit by the host device is smaller than a threshold.

1 .- 12 . (canceled) 
     
     
         13 . A storage device, comprising:
 a first storage configured to store first data from a host device;   a second storage configured to store a logical address for reading the first data in the first storage; and   a controller configured to, when a size of first data requested to be written into the first storage by the host device is smaller than a threshold, perform control of generating second data by adding the logical address to the first data and control of writing the second data into the first storage.   
     
     
         14 . The device according to  claim 13 , further comprising:
 a receiver configured to receive a read request for requesting to read first data from the host device;   a read controller configured to, when the receiver receives the read request, refer to logical-to-physical translation information indicative of an association between a physical address indicative of a position in the first storage and a logical address to identify a physical address associated with a logical address contained in the read request, and perform first read control of reading out information stored at a position indicated by an identified physical address.   
     
     
         15 . The device according to  claim 14 , wherein:
 the read controller is configured to, when a logical address is contained in information read out according to the first read control, perform second read control of reading out information stored at a position indicated by a physical address associated with the logical address, and   the read controller is configured to perform control of storing first data contained in information read out according to the second read control and the logical address in association with each other into the second storage.   
     
     
         16 . The device according to  claim 15 , wherein the read controller is configured to, when a logical address matching the logical address contained in the read request received by the receiver and first data are stored in association with each other in the second storage, perform third read control of reading out first data associated with a logical address matching the logical address contained in the read request from the second storage. 
     
     
         17 . The device according to  claim 14 , wherein the read controller is configured to perform control of storing at least a logical address used in the first read control into the second storage each time the read controller performs the first read control. 
     
     
         18 . The device according to  claim 17 , wherein the controller is configured to, when a size of first data requested to be written is smaller than the threshold, select a logical address used for reading within a predetermined time period before the first data is requested to be written from among logical addresses stored in the second storage and generate second data by adding a selected logical address to the first data. 
     
     
         19 . The device according to  claim 18 , wherein
 the second storage is configured to store time information indicative of time at which reading of information from the first storage is performed in association with each logical address, and   the controller is configured to, when a size of first data requested to be written is smaller than the threshold, select a logical address associated with time information indicative of time contained in the predetermined time period from among the logical addresses stored in the second storage and generate second data by adding a selected logical address to the first data.   
     
     
         20 . The device according to  claim 19 , wherein:
 the second storage includes:
 a third storage configured to store a logical address used in the first read control and the time information indicative of time at which reading according to the first read control is performed in association with each other; and 
 a fourth storage configured to store a logical address used in the second read control, first data read out according to the second read control, and time information indicative of time at which reading according to the second reading control is performed in association with one another, and 
   the controller is configured to, when a size of first data requested to be written is smaller than the threshold, select a logical address associated with time information indicative of time within the predetermined time period from among logical addresses stored in the third storage and the fourth storage and generate second data by adding a selected logical address to first data requested to be written.   
     
     
         21 . The device according to  claim 20 , wherein the third storage is a FIFO memory. 
     
     
         22 . The device according to  claim 19 , wherein:
 the second storage includes
 a third storage configured to store a logical address used in the first read control and time information indicative of time at which reading according to the first read control is performed in association with each other; and 
 a fourth storage configured to store a logical address used in the second read control and first data read out according to the second read control in association with each other, and 
   the controller is configured to, when a size of first data requested to be written is smaller than the threshold, select a logical address associated with time information indicative of time within the predetermined time period from among logical addresses stored in the third storage and generate second data by adding a selected logical address to first data requested to be written.   
     
     
         23 . The device according to  claim 22 , wherein the third storage is a FIFO memory. 
     
     
         24 . A storage device, comprising:
 a first storage configured to store first data from a host device;   a second storage configured to store a key address for searching first data associated with a key specified by the host device; and   a controller configured to, when a size of first data requested to be written into the first storage by the host device is smaller than a threshold, perform control of generating second data by adding a key address stored in the second storage to the first data and writing generated second data into the first storage.