Buffer Layer

Whenever we need to use a block, the block is copied to the primary memory. A pool of memory is allocated for this (Buffer). All the functions dealing with disk block is handled in buffer layer.

NITCBase has the ability to store ===32 Disk Blocks=== in buffer memory at a time. 64 KB.

HeadInfo

Each disk block contains 32 byte header fixed, that contains the metainformation. setHeader() and getHeader() takes the pointer to struct HeadInfo as argument.

struct HeadInfo {
    int32_t blockType;
    int32_t pblock;
    int32_t lblock;
    int32_t rblock;
    int32_t numEntries;
    int32_t numAttrs;
    int32_t numSlots;
    unsigned char reserved[4];
};

Attribute

Takes INT or STRING as value

union Attribute {
    double nVal;
    char sVal[ATTR_SIZE];
};