Answer 1)
Recording of transactions of financial nature is the basic/core objective of the accounting world. All the transactions which are of financial nature, either, transacted fully or partly are recorded in sequential way. Before preparing some rough drafts of any additional transactions, The official initial step of Book Keeping is to record all the transactions in journal, as and when they occur, following rules of debit and credit.
After posting these entries into journal, they are the then posted into different accounts of ledger. Objective of preparing ledger is to group similar transactions into one book and ascertaining summary of the entries of same nature at one place. However, re- posting of entries from journals and then to ledgers involves duplication of work as at first we look at documents and then prepare some additional ones. Then we record them in journal and further record them all again while posting them to ledgers. Thus we are doing same thing three times with lot of time and effort being wasted in duplication of work.
Answer 2)
Trial Balance is a statement of ledger account balances which is prepared to make ensure a reasonable accuracy of accounting. Although, not an assurance but agreement of trial balance is a reasonable evidence of absence of mathematical errors.
However, while using a mechanized accounting system, trial balance is automatically generated for the user and with high accuracy because the encrypted accounting software allows to enter only those transactions that are in balance and thus the chances of an unsuccessful trial balance is rare.
For Example, in Quick Books Accounting Software, Trial Balance is the first report available for the user. The Book-keepers, to a certain extent, can use this auto-generated trial balance to make sure that the transactions were entered correctly.
Works Cited
Epstein, L. (n.d.). Testing Your Trial Balance with Computerized Accounting Systems. Retrieved November 2nd, 2013, from Dummies.com: http://www.dummies.com/how-to/content/testing-your-trial-balance-with-computerized-accou.html
Grewal, T. (2009). Books of Accounts. In T. Grewal, Basic Accounting Concepts (pp. 12-25). New Delhi: Sharma.