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Bookkeeping is the recording of financial transactions, and is part of the process of accounting in business and other organizations. It involves preparing source documents for all transactions, operations, and other events of a business. Transactions include purchases, sales, receipts and payments by an individual person, organization or corporation. There are several standard methods of bookkeeping, including the single-entry and double-entry bookkeeping systems. While these may be viewed as "real" bookkeeping, any process for recording financial transactions is a bookkeeping process.
In computer science, ACID is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a sequence of database operations that satisfies the ACID properties is called a transaction. For example, a transfer of funds from one bank account to another, even involving multiple changes such as debiting one account and crediting another, is a single transaction.
Double-entry bookkeeping, also known as double-entry accounting, is a method of bookkeeping that relies on a two-sided accounting entry to maintain financial information. Every entry to an account requires a corresponding and opposite entry to a different account. The double-entry system has two equal and corresponding sides, known as debit and credit; this is based on the fundamental accounting principle that for every debit, there must be an equal and opposite credit. A transaction in double-entry bookkeeping always affects at least two accounts, always includes at least one debit and one credit, and always has total debits and total credits that are equal. The purpose of double-entry bookkeeping is to allow the detection of financial errors and fraud.
A database transaction symbolizes a unit of work, performed within a database management system against a database, that is treated in a coherent and reliable way independent of other transactions. A transaction generally represents any change in a database. Transactions in a database environment have two main purposes:
- To provide reliable units of work that allow correct recovery from failures and keep a database consistent even in cases of system failure. For example: when execution prematurely and unexpectedly stops in which case many operations upon a database remain uncompleted, with unclear status.
- To provide isolation between programs accessing a database concurrently. If this isolation is not provided, the programs' outcomes are possibly erroneous.
In computer science, a lock or mutex is a synchronization primitive that prevents state from being modified or accessed by multiple threads of execution at once. Locks enforce mutual exclusion concurrency control policies, and with a variety of possible methods there exist multiple unique implementations for different applications.
Debits and credits in double-entry bookkeeping are entries made in account ledgers to record changes in value resulting from business transactions. A debit entry in an account represents a transfer of value to that account, and a credit entry represents a transfer from the account. Each transaction transfers value from credited accounts to debited accounts. For example, a tenant who writes a rent cheque to a landlord would enter a credit for the bank account on which the cheque is drawn, and a debit in a rent expense account. Similarly, the landlord would enter a credit in the rent income account associated with the tenant and a debit for the bank account where the cheque is deposited.
In database systems, atomicity is one of the ACID transaction properties. An atomic transaction is an indivisible and irreducible series of database operations such that either all occur, or none occur. A guarantee of atomicity prevents partial database updates from occurring, because they can cause greater problems than rejecting the whole series outright. As a consequence, the transaction cannot be observed to be in progress by another database client. At one moment in time, it has not yet happened, and at the next it has already occurred in whole.
A transaction account, also called a checking account, chequing account, current account, demand deposit account, or share account at credit unions, is a deposit account or bank account held at a bank or other financial institution. It is available to the account owner "on demand" and is available for frequent and immediate access by the account owner or to others as the account owner may direct. Access may be in a variety of ways, such as cash withdrawals, use of debit cards, cheques and electronic transfer. In economic terms, the funds held in a transaction account are regarded as liquid funds. In accounting terms, they are considered as cash.
In computer science, an algorithm is called non-blocking if failure or suspension of any thread cannot cause failure or suspension of another thread; for some operations, these algorithms provide a useful alternative to traditional blocking implementations. A non-blocking algorithm is lock-free if there is guaranteed system-wide progress, and wait-free if there is also guaranteed per-thread progress. "Non-blocking" was used as a synonym for "lock-free" in the literature until the introduction of obstruction-freedom in 2003.
In functional programming, a monad is a structure that combines program fragments (functions) and wraps their return values in a type with additional computation. In addition to defining a wrapping monadic type, monads define two operators: one to wrap a value in the monad type, and another to compose together functions that output values of the monad type. General-purpose languages use monads to reduce boilerplate code needed for common operations. Functional languages use monads to turn complicated sequences of functions into succinct pipelines that abstract away control flow, and side-effects.
In computer science, compare-and-swap (CAS) is an atomic instruction used in multithreading to achieve synchronization. It compares the contents of a memory location with a given value and, only if they are the same, modifies the contents of that memory location to a new given value. This is done as a single atomic operation. The atomicity guarantees that the new value is calculated based on up-to-date information; if the value had been updated by another thread in the meantime, the write would fail. The result of the operation must indicate whether it performed the substitution; this can be done either with a simple boolean response, or by returning the value read from the memory location, thus "swapping" the read and written values.
A trial balance is an internal financial statement that lists the adjusted closing balances of all the general ledger accounts contained in the ledger of a business as at a specific date. This list will contain the name of each nominal ledger account in the order of liquidity and the value of that nominal ledger balance. Each nominal ledger account will hold either a debit balance or a credit balance. The debit balance values will be listed in the debit column of the trial balance and the credit value balance will be listed in the credit column. The trading profit and loss statement and balance sheet and other financial reports can then be produced using the ledger accounts listed on the same balance.
In concurrent programming, an operation is linearizable if it consists of an ordered list of invocation and response events, that may be extended by adding response events such that:
- The extended list can be re-expressed as a sequential history.
- That sequential history is a subset of the original unextended list.
In computer science, software transactional memory (STM) is a concurrency control mechanism analogous to database transactions for controlling access to shared memory in concurrent computing. It is an alternative to lock-based synchronization. STM is a strategy implemented in software, rather than as a hardware component. A transaction in this context occurs when a piece of code executes a series of reads and writes to shared memory. These reads and writes logically occur at a single instant in time; intermediate states are not visible to other (successful) transactions. The idea of providing hardware support for transactions originated in a 1986 paper by Tom Knight. The idea was popularized by Maurice Herlihy and J. Eliot B. Moss. In 1995, Nir Shavit and Dan Touitou extended this idea to software-only transactional memory (STM). Since 2005, STM has been the focus of intense research and support for practical implementations is growing.
Payment cards are part of a payment system issued by financial institutions, such as a bank, to a customer that enables its owner to access the funds in the customer's designated bank accounts, or through a credit account and make payments by electronic transfer with a payment terminal and access automated teller machines (ATMs). Such cards are known by a variety of names, including bank cards, ATM cards, client cards, key cards or cash cards.
In computer science and engineering, transactional memory attempts to simplify concurrent programming by allowing a group of load and store instructions to execute in an atomic way. It is a concurrency control mechanism analogous to database transactions for controlling access to shared memory in concurrent computing. Transactional memory systems provide high-level abstraction as an alternative to low-level thread synchronization. This abstraction allows for coordination between concurrent reads and writes of shared data in parallel systems.
Authorization hold is a service offered by credit and debit card providers whereby the provider puts a hold of the amount approved by the cardholder, reducing the balance of available funds until the merchant clears the transaction, after the transaction is completed or aborted, or because the hold expires.
This article describes the features in the programming language Haskell.
A concurrent hash-trie or Ctrie is a concurrent thread-safe lock-free implementation of a hash array mapped trie. It is used to implement the concurrent map abstraction. It has particularly scalable concurrent insert and remove operations and is memory-efficient. It is the first known concurrent data-structure that supports O(1), atomic, lock-free snapshots.
Join-patterns provides a way to write concurrent, parallel and distributed computer programs by message passing. Compared to the use of threads and locks, this is a high level programming model using communication constructs model to abstract the complexity of concurrent environment and to allow scalability. Its focus is on the execution of a chord between messages atomically consumed from a group of channels.
References
- ↑ Peyton Jones, Simon; Gordon, Andrew D.; Finne, Sigbjorn (1 January 1996). Written at Petersburg Beach, Florida. Concurrent Haskell. ACM SIGPLAN-SIGACT Symposium on Principles of Programming Languages (PoPL). New York, New York: Association for Computing Machinery (ACM). ISBN 978-0-89791-769-8. (Some sections are out of date as to later implementations.)
- ↑ The Haskell Hierarchical Libraries, Control.Concurrent Archived 2012-08-02 at archive.today
- ↑ Tim Harris, Simon Marlow, Simon Peyton Jones, and Maurice Herlihy. Composable Memory Transactions. ACM Symposium on Principles and Practice of Parallel Programming 2005 (PPoPP'05). 2005.
- ↑ Control.Concurrent.STM
