ISM means Indian Script Manager, developed by C-DAC (Centre for Development of Advanced Computing)  and is a registered trademark of C-DAC in India and other countries.

To run ISM with Windows based applications such as : CorelDraw, PageMaker etc. a minimum 486 DX based PC with 8 MB RAM, VGA display, 80 MB Hard disk and a mouse is required. While running ISM requires only 1.7 MB of RAM and about 100 KB per fonts. ISM takes around 4 MB of disk space for software. ISM is available in different versions. ISM Single Script means it can be used for one script only and ISM multiscript means it is for all scripts. Both of these packages have Diacritic Roman fonts.

Using ISM with MS Word : Before you start using ISM in Word it is necessary to switch off the AutoCorrect options in the Tools Menu Bar of the Word.

Start Microsoft Word --> Open Tools menu and choose AutoCorrect options --> a submenu with option like : Capitalize first, letter of the sentence, correct two initial capitals, capitalize names of days etc. Now you have to switch off all the options while typing. These options are created for English language, but the will create problem while typing in Indian languages. Again you have to switched off 'Autoformat' option, Straight Quotes with Smart Quotes and also Symbol characters.

ISM uses two types of fonts. These are - True type Fonts and Type-1 Fonts. Windows has true type Fonts by default. The Type-1 fonts are outline fonts. These fonts are not in Windows operating system. Therefore, for this an addition software ATM (Adobe Type Manager) is required. ATM is basically a font manager that manages bitmap fonts.

ISM can be used with Excel. Here you have to select the entire worksheet and then apply the desired font, because you need not select the font every time with a new cell.