1. Does any one know what is Software life cycle, it was a question asked in an interview.

Ans: it is nothing but Road Map - five phases like, Project Preparation, Blue print, Realisation, Final preparation and Go-live support.

2. In GL master we have a option "Balance in local currency" and "Account currency". What does it mean?

Ans: Account currency is that the GL account in which currency do you want to maintain. if you decided that you want maintain in company code currency, you can post any currency in that account.
If not, you want to maintain separate currency for that GL then exchange rate difference will come because the conversion rate.

Balance in local currency - some GL account can't be maintain on open item basis and can't in foreign currency like clearing account and discount account etc., in such case you can assign this indicator to show the balance in local currency.

3. In movement type(MM), what is value & quantity string I know it updates values and quantities in GL with mix of valuvation class, transaction key modifier and GL A/c. But how does it work when doing a mvt type?

Ans: Basically, the system does not know which GL has to be updated with what. here, we are giving a direction to the system to update the data.

What you said is correct, the system will update the value and qty in the material master. You would have seen some more fields also, like Movement indicator, consumption, value string and transaction event key etc.,

While creating a PO, the system will take the Movement type as a base, with MT, it will identify the MI(movement indicator - used to define whether it is goods movement for production order, purchase order, delivery note etc), and it will identify the consumption,( like it is assets, or consumption or sales order) and it will identify the value string ( it is must to assigned to movement type, through allocation of value string to movement type, system will automatically identify the GL ) and it will post the entry (dr/cr)in the GL based on the transaction and event key figure which is used to determine the debit and credit entry of a GL

4. In FI when doing Special GL transaction what determines the fields statues of the screen and why do we have so many screens followed by it. Is it determined by Posting Keys? is it to determine Account type for which we are using the Special GL and debit and credit?

A. In Field Status Group there are options like Suppress, optional, Required, Display. So that it is followed by so many screens and it is determined by posting key. Its both debit (or) (Both) credit.