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# Method for Calculating Disk Data Sector Availability

IP.com Disclosure Number: IPCOM000045869D
Original Publication Date: 1983-Apr-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 1 page(s) / 12K

IBM

## Related People

Churgovich, DM: AUTHOR [+3]

## Abstract

A method is disclosd for calculating data sector availability on a magnetic storage disk using fixed-point arithmetic.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 86% of the total text.

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Method for Calculating Disk Data Sector Availability

A method is disclosd for calculating data sector availability on a magnetic storage disk using fixed-point arithmetic.

Word Processing systems utilizing disk storage systems often do not have complex computational arithematic units or floating-point arithmetic. Such systems do require a system for calculating the percentage of data used by a data set on a disk. A disk normally has a fixed number of sectors, part of which are used as the volume table of contents (VTOC) and the remainder used as the data area.

The total number of data sectors available on a disk can be calculated by knowing the total number of sectors available and the sector number where the VTOC ends. Once the number of data sectors on the disk is known, the percent of disk space used by any given data set can readily be computed by dividing the number of sectors in the data set by the number of data sectors on the disk and multiplying it by 100. However, when the word processing device is not equipped with floating point arithmetic, the percentage value (PV) may be calculated by using the equation: PV=Xa + Xb + Xc where Xa is an integer value evenly divisible by 100, Xb is an integer value evenly divisible by 10, and

Xc is an integer ranging from 0 to 9.

To arrive at the values of Xa, Xb and Xc, the following three formulas are utilized: 1. Xa=((DSEC * 10)/DSA)) * 100

2. Xb=((DSEC * 100) - (( Xa/10) * DSA / DSA)) * 100

3. Xc=((DSEC * 100) // D...