You have been hired as a consultant for a company that wants to manufacture high-end bicycles. The owners of the new business have designed a bike that can be sold to cyclists that choose to compete. They have asked you to provide an evaluation and recommendation of the best manufacturing process. Use the information from this unit to write a recommendation to the owners. Include support for your choices.
3.7: Process Selection
- Page ID
- 65813
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ids355: Operations Management Wikispace: “Chapter 14, Summary: MRP and ERP
Review the information related to the use of manufacturing resource planning and enterprise resource planning. Both are useful within the organization. Resources are necessary to successful operations. One challenge that every manager faces is the decision of resource utilization. Pay attention to the benefits and requirements. Review the questions at the end of the summary. After answering the questions, compare your answers to the author’s answers.
Chapter 14: MRP & ERP
MRP
Items with dependent demand are items in which demand is derived from plans to make certain products (things like raw materials, parts, and assemblies). Example: The parts and materials that go into the making a car. Dependent demand tends to be “lumpy” whereas independent demand is fairly stable. MRP is a computer program that translates finished product requirements into time-phased requirements for each dependent demand items. The Bill of Materials, one of the three primary inputs of MRP, is useful because it is a list of all the assemblies, sub-assemblies, parts, and raw materials that are needed to produce one unit of a finished product.
In addition to MRP, this chapter provides information about ERP, which has an MRP core. ERP, which stands for “Enterprise Resource Planning” provides an expanded effort to integrate standardized record keeping that will permit information sharing among numerous dimensions of a business in order to direct the system more effectively. An ERP system typically has modular hardware and software units and “services” that communicate on a local area network.
An important issue in inventory management is determining a lot size to order or produce in independent and independent demand items. Lot sizing refers to choosing a lot size for ordering or production. For independent demand items managers use economic order sizes and economic production quantities. For dependent demand systems managers can choose larger variety plans to determine the lot sizes. Dependent demand tends to be sporadic or “lumpy”. The goal of independent demand and dependent demand systems is to minimize the sum of ordering cost and holding cost.
MRP Input
MRP uses three primary sources for information: master schedule, bill-of-materials file, and an inventory records file. Master schedule relates to product demand and timeline. It states what end items need to be produced, when they are needed and how much are needed. Bill of materials relates to product composition. It lists all of the raw materials, parts, sub-assemblies and assemblies required to manufacture one item. Inventory records relate to inventory. They consist of status information on an item sorted by time period. Status information consists of gross requirements, scheduled receipts and expected amount on hand.
MRP Output
MRP systems have capabilities of providing management with a wide range of outputs. These typically include primary reports and secondary reports. Primary Reports – production and inventory planning and control are part of primary reports. They usually include: Planned orders – a schedule indicating the amount and timing of future orders
Order releases – authorizing the execution of planned orders
Changes to planned orders – revisions of due dates or order quantities/ cancellation of orders.
Secondary Reports – performance control, planning, and exceptions belong to secondary reports
Performance-control reports – measure deviations from plans such as deliveries and stockouts, as well as providing info that can be used to assess cost performance.
Planning reports – predict future inventories, procurement contracts and data for future assessment of material requirements.
Exception reports – recognizes inconsistencies within the report such as errors in overdue or late orders, etc. pg 661
BENEFITS AND REQUIREMENTS OF MRP
Benefits
MRP enables managers to: determine the quantities for a given order size, know when to release orders for each component, and to be alerted when items need attention. Other benefits of MRP include:
1) Low levels of in process inventories
2) The Ability to keep track of material requirements
3) The ability to evaluate capacity requirements generated by a given master schedule
4) A means of allocating production time
5) The ability to easily determine inventory usage by backflushing.
Backflushing is a procedure in which an end item’s bill of materials (BOM) is periodically exploded to determine the quantities of the various components that were used to make the item. The people who are typical users of a MRP system in a typical manufacturing company are production managers, purchasing managers, inventory managers, and customer representatives.The benefits of MRP depend primarily on the use of computer to maintain up-to-date information on material requirement.
Requirements
The benefits of MRP primarily depend on the ability to maintain up-to-date and accurate information. In order to implement and operate an effective MRP system, it is necessary to have:
1) a computer and the necessary software programs to handle computations and maintain records
2) Accurate and up-to date master schedules, Bills of materials, Inventory records
3) Integrity of file data.
MRP II
Manufacturing Resources Planning II developed in the 1980s after manufacturers realized MRP had additional needs. MRP II expanded the use of MRP by adding features essential to the use of other functional areas, marketing and finance to enable the use of short-range capacity requirements. Material requirements are essential for the use of MRP II. MRP II systems are good at simulation and help answer “what if” questions i.e., to foresee the consequences of their options and other alternatives. With the new function areas added, the manufacturing company is able to develop a master production schedule. MRP generates the materials needed and schedules the requirements, where managers can obtain a more detailed capacity requirements. Capacity requirements is the process of determining short-range capacity requirements.
MRP Considerations
MRP Inputs: The master schedule should cover a period that is at least equivalent to the cumulative lead time (the sum of the lead times that sequential phases of a process require, from ordering of parts or raw materials to completion of final assembly.)
Safety Stock: Needed in case there is variability due to bottleneck processes causing shortages, shortages caused by late orders and/or fabrications, or assembly lines are longer than expected.
Safety Time: Used when lead times vary to allow tasks to be completed well ahead of schedule to eliminate the probability of shortage.
Lot-for-Lot (L4L) ordering: The order or run size is set equal to the demand for that period.
Economic Order Quantity (EOQ): Can lead to minimum costs if usage of item is fairly uniform.
Fixed Period Ordering: Provides coverage for some predetermined number of periods.
System Stability: Without stability, changes in order quantity and/or timing can render material requirements plans virtually useless.
System Nervousness: How a system reacts to changes.
This chapter goes into detail about the advantages and nature of MRP processing, as well as describing the applications of MRP in different industries. The chapter then describes the evolution of MRP to MRPII, which expanded the scale of materials planning. MRPII gave managers the ability to ask “what if” questions, and provided them with a more precise decision making tool. In addition to MRP, enterprise resource planning (ERP) or the “third generation,” is also described. ERP gave companies the ability to incorporate all departments and functions company-wide on a single system. The benefits of ERP are substantial; however, it must be noted that high training, maintenance, and initial start up costs are too high.
QUESTIONS:
1. The choosing of a lot size for ordering or __ is considered lot sizing. p.g. 662
a. production
b. delivery
c. cost
d. inventory
e. None of the above
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Answer: a. production
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2. The model that leads to minimum costs,when the usage is fairly uniform is: p.g. 662
a. economic order quantity model
b. fixed-period ordering
c. lot-for-lot ordering
d. independent demand
e. dependent demand
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Answer: a. Economic order quantity model
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3. The primary goal of management is to minimize cost of ? p.g. 662
a. production
b. delivery
c. good
d. inventory
e. All of the Above
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Answer: d. inventory
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4. What is the simplest method of lot sizing? p.g. 662
a. Lot for lot ordering
b. economic order quantity model
c. fixed-period ordering
d. independent demand
e. dependent demand
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Answer: a. lot for lot ordering
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5. Which type of ordering provides coverage for some predetermined number of periods? p.g. 662
a. lot for lot ordering
b. economic order quantity model
c. fixed period ordering
d. independent demand
e. dependent demand
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Answer: c. fixed period ordering
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6. MPR is designed to answer all of the questions except: p.g. 649
a. How much is needed?
b. What is the time constraint?
c. When is it needed?
d. What is needed?
e. None of the above
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Answer: b. what is the time constraint?
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7. A Master Schedule contains which of the following?:
A. Which end items are to be produced
B. When end items will be needed
C. What quality of end items will be needed
D. All of the above
E. A and B only
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Answer: E (pg 650) quantity, not quality.
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8. Restructuring the bill of materials, so that multiple occurrences of a component will coincide with the lowest level at which the component occurs is known as:
A. one-level coding
B. component minimizing
C. low-level coding
D. MRP minimization
E. None of the above
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Answer: C (pg 653)
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9. All of the following are Primary Reports except:
A. Planning Reports
B. Planned Orders
C. Changes
D. Order Releases
E. None of the above
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Answer: A (pg 661)
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10. What is the expanded approach to production resource planning that involves other areas of a firm in the planning process and enables capacity requirements planning?
A. ERP
B. MRP II
C. DRP II
D. MRP Extended
E. None of the above
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Answer: B (pg 664)
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11. ERP software provides:
A. A system to capture and make data available in real time
B. A capability to assess the feasibility of a proposed plan
C. A set of tools for planning and monitoring business processes to achieve goals of the organization
D. A and C
E. None of the above
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Answer: D (pg 669)
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12. Which of the following is NOT included in the billing of materials?
A. raw materials
B. labor hours
C. parts
D. subassemblies
E. assemblies processes
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Answer: B, 638
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13. What is a product structure tree?
A. visual depiction of the requirements in a bill of materials where all components are listed by levels
B. visual depiction of the requirements in a master schedule where all products are listed by demand.
C. visual depiction of the requirements in inventory records where all components are listed by status.
D. all of the above
E. none of the above
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Answer: A, 638
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14. Which of the following is NOT a primary source of information for MRP?
A. master schedule
B. inventory records
C. bill of materials
D. planned orders
E. all of the above are not primary sources of information for MRP
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Answer: D, 637
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15. The sum of the lead times required by sequential phases of a process is known as:
A. LTSP
B. critical path
C. cumulative lead time
D. master schedule
E. horizon plan
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Answer: C, 638
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16. What is an advantage of a regenerative system?
A. reflecting changes as they occur
B. less processing costs
C. up-to-date information for planning purposes
D. none of the above
E. B and C
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Answer: B, 663
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17. What are classified as the main reports used by management?
A. Planning Reports
B. Performance-Control Reports
C. Exception Reports
D. Primary Reports
E. Secondary Reports
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Answer: D p.661
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18. Primary Reports include which of the following?
A. Planned Orders
B. Order releases
C. Changes to planned orders
D. All the above
E. Only A and C
[reveal-answer q=”489631″]Show Solution[/reveal-answer]
[hidden-answer a=”489631″]
Answer: D p.661
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19. Secondary Reports include which of the following?
A. Performance-control reports
B. Planning Reports
C. Exception Reports
D. All the above
E. Only A & B
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[hidden-answer a=”696537″]
Answer: D p.661
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20. What major function is involved with Planning Reports?
A. Evaluating system operations
B. Calling attention to major discrepancies in orders
C. Forecasting Future Inventory Requirement Decisions
D. All of the Above
E. None of the Above
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Answer: C p.661
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21. Which report contains production and inventory planning and control?
A. Primary Report
B. Secondary Report
C. Planning Report
D. Exception Report
E. Performance-Control Report
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Answer: A p.661
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22. What is the most expensive of the following processes?
A. MRP
B. MRPII
C. ERP
D. They all cost the same
E. A & B only
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Answer: C p.661
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23. What recognizes inconsistencies within the report such as errors in overdue or late orders, etc?
A. Performance-control reports
B. Planning reports
C. Planned orders
D. Exception Reports
E. B & C only
[reveal-answer q=”867258″]Show Answer[/reveal-answer]
[hidden-answer a=”867258″]
Answer: D p.661
[/hidden-answer]
24. Which of the following is not a benefit of an MRP system?
A. The ability to keep track of material requirements
B. A means of allocating production time
C. The ability to easily determine inventory usage by backflushing
D. High Levels of in process inventory
E. All of the above are benefits of an MRP system
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Answer: D (Page 663)
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25. is a procedure in which an end item’s bill of material is periodically exploded to determine the quantities of the various components that were used to make the items.
A. Backloading
B. Backflushing
C. Backwashing
D. Backflowing
E. None of the above
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Answer: B (Page 663)
[/hidden-answer]
26. The benefit of an MRP system depends on the ability to have large amounts of unorganized information readily accessible.
A. True
B. False
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Answer: False (Page 663)
[/hidden-answer]
27. Which of the following is one of the requirements for an MRP system?
A. A computer
B. Accurate and up to date information
C. Integrity of data
D. None of the Above
E. All of the Above
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Answer: E (Page 664)
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28. Which of the following is/are (a) factor(s) that causes problems in an MRP system?
A. assumption of constant lead times
B. products being produced differently from the bill of materials
C. failure to alter a bill of materials when customizing a product
D. Inaccurate forecast
E. All of the above
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Answer: E (Page 664)
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29. In addition to manufacturing resources needed for the master production plan, what else is the financial department in charge of?
A. Amount of resources
B. Timing
C.Work Time
D. A & B
E. B & C
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Answer: D. (Page 638)
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30. MRP II has restrictions and times where they can make changes to the orders/production. What is this called?
A. Time Series
B. Time Fences
C. Time Based System
D. Time Based Strategy
E. None of the above
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Answer: B. (Page 666)
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31. Manufacturing Company generates the Master Schedule according to
A.What is possible
B. What is Demanded
C. What is Given
D. What is Needed
E. None of the above
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Answer: D (Page 637)
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32.What is the percentage of capacity requirement for the machine, if 150 units of Product A are scheduled, when the machines standard time is 1.9 hours and labor standard time of 2.3 hours?
A. 72.4%
B. 82.6%
C.12.10%
D.10.6%
E. None of the above
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Answer B. (Page 656)
[/hidden-answer]
33. MRP is essential in establishing requirements for capacity, but it also has a downfall. What is it?
A. Cannot aggregate demand from all sources
B. Cannot plan for amount of requirements and timing
C. Cannot distinguish between a feasible Master Schedule and a nonfeasible schedule.
D Cannot make changes to the Master Schedule once it is in process.
E. None of the above
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Answer: C (Page 654)
[/hidden-answer]
34 . _ is the sum of the lead times that sequential phases of a process require, from ordering of parts or raw materials to completion of final assembly.
a. Overall lead time
b. Safety time
c. Cumulative lead time
d. Completion time
e. Slack
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Answer: C.(p.g 650)
[/hidden-answer]
35. Which ordering method would you use if the use of the item is fairly uniform?
a. Economic order quantity model
b. L4L
c. Fixed Period Ordering
d. BOM
e. Automated Ordering
[reveal-answer q=”938404″]Show Answer[/reveal-answer]
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Answer: A..(p.g. 662)
[/hidden-answer]
question must have 5 choices
36. System sensitivity is how a system reacts to changes.
a. True
b. False
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Answer: B.(need number page of answer)
[/hidden-answer]
37. The concept of safety time is often used when…
a. There is variability due to bottleneck processes causing shortages
b. Used when lead times vary
c. Shortages caused by late orders and/or fabrications
d. Assembly lines are longer than expected
e. All of the above
[reveal-answer q=”218444″]Show Answer[/reveal-answer]
[hidden-answer a=”218444″]
Answer: B.(need number page of answer)
[/hidden-answer]
38. The master schedule should cover a period that is at least equivalent to the…
a. CRP
b. Closed loop MRP
c. Time buckets
d. Cumulative lead time
e. Cumulative lead time subtracted by time buckets
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Answer: D.(p.g. 650)
[/hidden-answer]
39. What is considered the “third generation of manufacturing software.”
a. Y2K
b. MRP
c. MRPII
d. ERP
e. None of the above
[reveal-answer q=”973921″]Show Answer[/reveal-answer]
[hidden-answer a=”973921″]
Answer: D (P.668)
[/hidden-answer]
40. Which of the following is NOT a feature of MRP?
a. Planned-order releases
b. Calculating component requirements
c. Master scheduling
d. Time-phasing of requirements
e. All choices are a feature of MRP
[reveal-answer q=”939052″]Show Answer[/reveal-answer]
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Answer: C (P.654)
[/hidden-answer]
41. Which of the following is true of ERP?
a. Low start up cost
b. Requires intensive employee training
c. Low maintenance cost
d. Non time consuming
e. All choice are false
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Answer: B (P.670)
[/hidden-answer]
42. Which of the following is NOT true of MRP?
a. Requires a computer and the necessary software programs to handle computations and maintain records
b. Requires at least one hundred working computers
c. Requires accurate and up to date inventory records
d. Requires accurate and up to date master schedules and records
e. Integrity of file data
[reveal-answer q=”252758″]Show Answer[/reveal-answer]
[hidden-answer a=”252758″]
Answer: B (P.650)
[/hidden-answer]
43. What is ERP?
a. Entry Resource Pricing systems
b. The second generation manufacturing program
c. enterprise Resource Planning
d. Enterprise Report Planning
e. All the Above
[reveal-answer q=”733204″]Show Answer[/reveal-answer]
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Answer: C (P.668)
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Wikipedia: “Methods of Production”
Read this source. Different types of production can be used within a manufacturing organization. This source provides information about these types of production. Pay particular attention to the batch and flow production.
Methods of production
Production methods fall into three main categories; however, all production methods can be assisted with CAM and CAD equipment (Computer Aided Manufacture and Computer Aided Design – respectively).
Job Production and Prototype Production
Job Production is used when a product is produced with the labor of one or few workers and is scarcely used for bulk and large scale production. It is mainly used for one-off products or prototypes, as it is inefficient; however, quality is greatly enhanced with job production compared to other methods. Individual wedding cakes and made-to-measure suits are examples of job production. New small firms often use job production before they get a chance or have the means to expand. Job Production is highly motivating for workers because it gives the workers an opportunity to produce the whole product and take pride in it.
Boutique Manufacturing
Contrary to jobbing production, the method Boutique Manufacturing is suitable for the production of very small to small batches, i.e. orders of a few units up to several dozens of similar or equal goods. The workflow organization of a Boutique Manufacturing entity can be a mixture of both jobbing and batch production but involves higher standardization than job production. Boutique Manufacturing is often organized with single workplaces or production cells carrying out a number of subsequent production steps until completion of certain components or even the whole product; large assembly lines are generally not used. The flexibility and variety of products able to be produced in the entity therefore are much higher than with the more standardized method of batch production.
Batch Production
Batch production is the method used to produce or process any product in groups or batches where the products in the batch go through the whole production process together. An example would be when a bakery produces each different type of bread separately and each object (in this case, bread) is not produced continuously. Batch production is used in many different ways and is most suited to when there is a need for a quality/quantity balance. This technique is probably the most commonly used method for organizing manufacture and promotes specialist labor, as very often batch production involves a small number of persons. Batch production occurs when many similar items are produced together. Each batch goes through one stage of the production process before moving onto next stage.
Flow Production
Flow production (Process Production) is also a very common method of production. Flow production is when the product is built up through many segregated stages; the product is built upon at each stage and then passed directly to the next stage where it is built upon again. The production method is financially the most efficient and effective because there is less of a need for skilled workers.
Computer Aided Manufacture and Computer Aided Design
Computer Aided Design (CAD) is the use of a wide range of computer-based software tools that assist engineers and architects alike.
Wikipedia: “Continuous Production”
Read this source to explore the way that continuous production works in a manufacturing environment. This is important because often operations managers must make choice about what type of method is appropriate given the requirements of the business.
Continuous production
Continuous usually means operating 24 hours per day, seven days per week with infrequent maintenance shutdowns, such as semi-annual or annual. Some chemical plants can operate for more than one or two years without a shutdown. Blast furnaces can run four to ten years without stopping. Continuous production is a flow production method used to manufacture, produce, or process materials without interruption. Continuous production is called a continuous process or a continuous flow process because the materials, either dry bulk or fluids that are being processed are continuously in motion, undergoing chemical reactions or subject to mechanical or heat treatment. Continuous processing is contrasted with batch production.
Common Processess
Some common continuous processes are the following:
- Oil refining
- Chemicals
- Synthetic fibers
- Fertilizers
- Pulp and paper
- Blast furnace (iron)
- Metal smelting
- Power stations
- Natural gas processing
- Sanitary waste water treatment
- Continuous casting of steel
- Rotary kilns for calcining lime or cement
- Float glass
Production workers in continuous production commonly work in rotating shifts.
Processes are operated continuously for practical as well as economic reasons. Most of these industries are very capital intensive and the management is therefore very concerned about lost operating time.
Shutting down and starting up many continuous processes typically results in off quality product that must be reprocessed or disposed of. Many tanks, vessels and pipes cannot be left full of materials because of unwanted chemical reactions, settling of suspended materials or crystallization or hardening of materials. Also, cycling temperatures and pressures from starting up and shutting down certain processes (line kilns, boilers, blast furnaces, pressure vessels, etc.) may cause metal fatigue or other wear from pressure or thermal cycling.
In the more complex operations there are sequential shut down and start up procedures that must be carefully followed in order to protect personnel and equipment. Typically a start up or shut down will take several hours.
Continuous processes use process control to automate and control operational variables such as flow rates, tank levels, pressures, temperatures and machine speeds.
Semi-continuous Processes
Many processes such as assembly lines and light manufacturing that can be easily shut down and restarted are today considered semi-continuous. These can be operated for one or two shifts if necessary.
History
The oldest continuous flow processes is the blast furnace for producing pig iron. The blast furnace is intermittently charged with ore, fuel and flux and intermittently tapped for molten pig iron and slag; however, the chemical reaction of reducing the iron and silicon and later oxidizing the silicon is continuous.
Semi-continuous processes, such as machine manufacturing of cigarettes, were called “continuous” when they appeared.
Many truly continuous processes of today were originally batch operations.
The Fourdrinier paper machine, patented in 1799, was one of the earliest of the industrial revolution era continuous manufacturing processes. It produced a continuous web of paper that was formed, pressed, dried and reeled up in a roll. Previously paper had been made in individual sheets.
Another early continuous processes was Oliver Evans’es flour mill (ca. 1785), which was fully automated.
Early chemical production and oil refining was done in batches until process control was sufficiently developed to allow remote control and automation for continuous processing. Processes began to operate continuously during the 19th century. By the early 20th century continuous processes were common.
Shut-downs
In addition to performing maintenance, shut downs are also when process modifications are performed. These include installing new equipment in the main process flow or tying-in or making provisions to tie-in sub-processes or equipment that can be installed while the process is operating.
Shut-downs of complicated processes may take weeks or months of planning. Typically a series of meetings takes place for co-ordination and planning. These typically involve the various departments such as maintenance, power, engineering, safety and operating units.
All work is done according to a carefully sequenced schedule that incorporates the various trades involved, such as pipe-fitters, millwrights, mechanics, laborers, etc., and the necessary equipment (cranes, mobile equipment, air compressors, welding machines, scaffolding, etc.) and all supplies (spare parts, steel, pipe, wiring, nuts and bolts) and provisions for power in case power will also be off as part of the outage. Often one or more outside contractors perform some of the work, especially if new equipment is installed.
Safety
Safety meetings are typically held before and during shutdowns. Other safety measures include providing adequate ventilation to hot areas or areas where oxygen may become depleted or toxic gases may be present and checking vessels and other enclosed areas for adequate levels of oxygen and insure absence of toxic or explosive gases. Any machines that are going to be worked on must be electrically disconnected, usually through the motor starter, so that it cannot operate. It is common practice to put a padlock on the motor starter, which can only be unlocked by the person or persons who is or are endangered by performing the work. Other disconnect means include removing couplings between the motor and the equipment or by using mechanical means to keep the equipment from moving. Valves on pipes connected to vessels that workers will enter are chained and locked closed, unless some other means is taken to insure that nothing will come through the pipes.
Continuous Processor (Equipment)
Continuous Production can be supplemented using a Continuous Processor. Continuous Processors are designed to mix viscous products on a continuous basis by utilizing a combination of mixing and conveying action. The Paddles within the mixing chamber (barrel) are mounted on two co-rotating shafts that are responsible for mixing the material. The barrels and paddles are contoured in such a way that the paddles create a self-wiping action between themselves minimizing buildup of product except for the normal operating clearances of the moving parts. Barrels may also be heated or cooled to optimize the mixing cycle. Unlike an extruder, the Continuous Processor void volume mixing area is consistent the entire length of the barrel ensuring better mixing and little to no pressure build up. The Continuous Processor works by metering powders, granules, liquids, etc. into the mixing chamber of the machine. Several variables allow the Continuous Processor to be versatile for a wide variety of mixing operations:
- Barrel Temperature
- Agitator speed
- Fed rate, accuracy of feed
- Retention time (function of feed rate and volume of product within mixing chamber)
Continuous Processors are used in the following processes:
- Compounding
- Mixing
- Kneading
- Shearing
- Crystallizing
- Encapsulating
The Continuous Processor has an unlimited material mixing capabilities but, it has proven its ability to mix:
- Plastics
- Adhesives
- Pigments
- Composites
- Candy
- Gum
- Paste
- Toners
- Peanut Butter
- Waste Products
Wikipedia: “Batch Processing”
Read this source to explore the history and usefulness of batch processing in a manufacturing company. Consider how batch processing is used in today’s manufacturing environments.
Batch Processing
Batch processing is the execution of a series of programs (“jobs”) on a computer without manual intervention.
Jobs are set up so they can be run to completion without human interaction. All input parameters are predefined through scripts, command-line arguments, control files, or job control language. This is in contrast to “online” or interactive programs which prompt the user for such input. A program takes a set of data files as input, processes the data, and produces a set of output data files. This operating environment is termed as “batch processing” because the input data are collected into batches or sets of records and each batch is processed as a unit. The output is another batch that can be reused for computation.
Benefits
Batch processing has these benefits:
- It can shift the time of job processing to when the computing resources are less busy.
- It avoids idling the computing resources with minute-by-minute manual intervention and supervision.
- By keeping high overall rate of utilization, it amortizes the computer, especially an expensive one.
- It allows the system to use different priorities for interactive and non-interactive work.
- Rather than running one program multiple times to process one transaction each time, batch processes will run the program only once for many transactions, reducing system overhead.
History
Batch processing has been associated with mainframe computers since the earliest days of electronic computing in the 1950s. There were a variety of reasons why batch processing dominated early computing. One reason is that the most urgent business problems for reasons of profitability and competitiveness were primarily accounting problems, such as billing. Billing may conveniently be performed as a batch-oriented business process, and practically every business must bill, reliably and on-time. Also, every computing resource was expensive, so sequential submission of batch jobs on punched cards matched the resource constraints and technology evolution at the time. Later, interactive sessions with either text-based computer terminal interfaces or graphical user interfaces became more common. However, computers initially were not even capable of having multiple programs loaded into the main memory.
Batch processing is still pervasive in mainframe computing, but practically all types of computers are now capable of at least some batch processing, even if only for “housekeeping” tasks. That includes UNIX-based computers, Microsoft Windows, Mac OS X (whose foundation is the BSD Unix kernel), and even smartphones. Even as computing in general becomes more pervasive, batch processing is unlikely to lose its significance.
Modern systems
Batch applications are still critical in most organizations in large part because many common business processes are amenable to batch processing. While online systems can also function when manual intervention is not desired, they are not typically optimized to perform high-volume, repetitive tasks. Therefore, even new systems usually contain one or more batch applications for updating information at the end of the day, generating reports, printing documents, and other non-interactive tasks that must complete reliably within certain business deadlines.
Modern batch applications make use of modern batch frameworks such as Jem The Bee, Spring Batch or implementations of JSR 352 written for Java, and other frameworks for other programming languages, to provide the fault tolerance and scalability required for high-volume processing. In order to ensure high-speed processing, batch applications are often integrated with grid computing solutions to partition a batch job over a large number of processors, although there are significant programming challenges in doing so. High volume batch processing places particularly heavy demands on system and application architectures as well. Architectures that feature strong input/output performance and vertical scalability, including modern mainframe computers, tend to provide better batch performance than alternatives.
Scripting languages became popular as they evolved along with batch processing.
Batch Window
A batch window is “a period of less-intensive online activity”, when the computer system is able to run batch jobs without interference from online systems.
Many early computer systems offered only batch processing, so jobs could be run any time within a 24-hour day. With the advent of transaction processing the online applications might only be required from 9:00 a.m. to 5:00 p.m., leaving two shifts available for batch work, in this case the batch window would be sixteen hours. The problem is not usually that the computer system is incapable of supporting concurrent online and batch work, but that the batch systems usually require access to data in a consistent state, free from online updates until the batch processing is complete.
In a bank, for example, so-called end-of-day (EOD) jobs include interest calculation, generation of reports and data sets to other systems, printing statements, and payment processing.
As requirements for online systems uptime expanded to support globalization, the Internet, and other business requirements the batch window shrank and increasing emphasis was placed on techniques that would require online data to be available for a maximum amount of time.
Common Batch Processing Usage
Databases
Batch processing is also used for efficient bulk database updates and automated transaction processing, as contrasted to interactive online transaction processing (OLTP) applications. The extract, transform, load (ETL) step in populating data warehouses is inherently a batch process in most implementations.
Images
Batch processing is often used to perform various operations with digital images such as resize, convert, watermark, or otherwise edit image files.
Conversions
Batch processing may also be used for converting computer files from one format to another. For example, a batch job may convert proprietary and legacy files to common standard formats for end-user queries and display.
Notable Batch Scheduling and Execution Environments
UNIX utilizes cron and at facilities to allow for scheduling of complex job scripts. Windows has a job scheduler. Most high-performance computing clusters use batch processing to maximize cluster usage.
The IBM mainframe z/OS operating system or platform has arguably the most highly refined and evolved set of batch processing facilities owing to its origins, long history, and continuing evolution. Today such systems commonly support hundreds or even thousands of concurrent online and batch tasks within a single operating system image. Technologies that aid concurrent batch and online processing include Job Control Language (JCL), scripting languages such as REXX, Job Entry Subsystem (JES2 and JES3),Workload Manager (WLM), Automatic Restart Manager (ARM), Resource Recovery Services (RRS), DB2 data sharing, Parallel Sysplex, unique performance optimizations such as HiperDispatch, I/O channel architecture, and several others.
Unit 3 Discussion, Part 2
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