Browse Prior Art Database

Low-Cost RAM Addressing for Variable Sector Size

IP.com Disclosure Number: IPCOM000117407D
Original Publication Date: 1996-Feb-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Ishibashi, K: AUTHOR [+3]

Abstract

Disclosed is a method of providing the variable sector size into small hard disk drive without adding any complicated hardware address calculator and/or software resources for sector buffer addressing.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 100% of the total text.

Low-Cost RAM Addressing for Variable Sector Size

      Disclosed is a method of providing the variable sector size
into small hard disk drive without adding any complicated hardware
address calculator and/or software resources for sector buffer
addressing.

      The linear addressing is the most popular method to place the
pages on the buffer space.  With this method, to get the base address
of a certain buffer page is not an easy job because a multiplying
operation is required (Fig. 1).

      If the sector size is power of 2, the calculation is much
easier than other cases.  The sector sizes which should be supported
by small Hard Disk Drive (HDD) can be written as (power of 2) +4, 8,
10, etc.

      This invention describes the way of placing buffer page by
dividing it into two parts, power of 2 (PART-A) and the rest
(PART-B).  Fig. 2 shows the the case of sector size = 256+10 words,
as an example.  The total buffer space is divided into 2 blocks.  The
1st block takes the 15/16 of the total buffer space and the 2nd one
takes 1/16.  The PART-A will be placed in the larger block and PART-B
will be in the smaller one.  Note, PART-B must be placed at the
address of power of 2 with the 6 words in the unused space.

      With this placement of the buffer page X, the base address for
both of PART-A and PART-B can be easily calculated.