Digital Business Networks 1st Edition
Dooley
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Digital Business Networks (Dooley)
Chapter 8 Local Area Networks and Backbone Networks
8.1 Multiple Choice Questions
1) Logical components, like physical components, also need to be installed, configured, and ________.
A) transported
B) maintained
C) portable
D) packaged
Answer: B
Diff: 2 Page Ref: 140
2) Physical components are frequently referred to as ________.
A) flatware
B) software
C) hardware
D) goldware
Answer: C
Diff: 2 Page Ref: 140
3) Logical components are usually ________, but may also include procedures that define how a particular task should be accomplished.
A) transferable
B) united
C) hardware
D) software
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Answer: D
Diff: 1 Page Ref: 140
4) ________ is a set of programmed instructions that tell a device how to perform its functions; it is executed, or run, electronically, using some type of computer processor.
A) Software
B) Hardware
C) Boxware
D) Serverware
Answer: A
Diff: 1 Page Ref: 140
5) A ________ refers to how the pieces of a network are connected.
A) topology
B) box check
C) mapology
D) builder
Answer: A
Diff: 3 Page Ref: 140
6) Ethernet and token ring are ________.
A) packets
B) pliers
C) protocols
D) packages
Answer: C
Diff: 2 Page Ref: 141
7) Which company introduced ring topology?
A) Thomson Consumer Electronics
B) Dell
C) Sony
D) IBM
Answer: D
Diff: 3 Page Ref: 142
8) MAU stands for ________.
A) Multiple Alternate Usages
B) Media Access Unit
C) Medium Access Usage
D) Multiple Access User
Answer: B
Diff: 1 Page Ref: 142
9) CSMA/CD stands for ________.
A) Carrier Sense Multiple Access/Collision Detection
B) Communication Sense Multiple Access/Communication Detection
C) Carrier Sense Millennium Access/Communication Detection
2
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D) Carrier Services Multiple Access/Commuter Detection
Answer: A
Diff: 2 Page Ref: 143
10) NIC stands for ________.
A) Natal Interest Communication
B) New Interfacer Compartment
C) Network Interface Card
D) Next Interuser Control
Answer: C
Diff: 2 Page Ref: 143
11) What is a NIC also known as?
A) buffer
B) hider card
C) proximity card
D) adapter card
Answer: D
Diff: 1 Page Ref: 143
12) A NIC's ________ is used to temporarily hold data to be processed and assists in speeding up the performance of the LAN.
A) cache (or buffer)
B) pile
C) lodestar
D) magistrate card
Answer: A
Diff: 2 Page Ref: 144
13) DMA stands for ________.
A) detection mode analysis
B) direct memory access
C) division mode action
D) diverse memory action
Answer: B
Diff: 1 Page Ref: 144
14) What is the technique that incorporates a CPU (central processing unit) on the NIC? Through this technique, a NIC can process incoming data without having to wait for the host's CPU to do the job.
A) home control
B) train following
C) car controlling
D) bus mastering
Answer: D
Diff: 2 Page Ref: 144
15) An Ethernet NIC address consists of 48 bits composed of ________ hexadecimal digits.
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A) 12
B) 10
C) 8
D) 6
Answer: A
Diff: 3 Page Ref: 144
16) What kind of LAN medium is most commonly used in newer buildings?
A) UTP
B) HTP
C) LTP
D) STP
Answer: A
Diff: 1 Page Ref: 145
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17) Which of the following is a higher-quality UTP than Cat 5?
A) Cat Z
B) Cat 3
C) Cat 4
D) Cat 6
Answer: D
Diff: 2 Page Ref: 145
18) Which servers are very popular for their design, modularity, size, and cost-efficiency?
A) Sliver
B) Elongated
C) Stick
D) Blade
Answer: D
Diff: 3 Page Ref: 146
19) Servers require controlling and managing software, which is called a(n) ________ or ________.
A) NAS, SAS
B) NOS, SOS
C) UPR, APR
D) EMT, NOT
Answer: B
Diff: 3 Page Ref: 146
20) Typical login components include ________.
A) a user ID and a password
B) an icon and an avatar
C) a name and a number
D) an address and an identification number
Answer: A
Diff: 1 Page Ref: 147
21) A type of LAN that uses dedicated servers and independent clients is called ________.
A) a passenger/pilot model
B) a farmer/field model
C) a client/server model
D) a super/supra model
Answer: C
Diff: 3 Page Ref: 147
22) Which type of network is less conducive to using more than 15 user stations?
A) peer-to-peer network
B) friendly network
C) minor network
D) major network
Answer: A
Diff: 3 Page Ref: 147
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23) ________ is the most common LAN architecture.
A) Ethanol
B) Ether
C) WAN
D) Ethernet
Answer: D
Diff: 1 Page Ref: 147
24) There are Ethernet LANs, including standard, Fast, and Gigabit Ethernet, that use ________ rather than hubs.
A) turns
B) nets
C) wires
D) switches
Answer: D
Diff: 2 Page Ref: 147
25) The defining characteristics of an Ethernet bus are ________ and ________.
A) abruption, consolation
B) contention, collision
C) abstention, litigation
D) prosecution, collusion
Answer: B
Diff: 3 Page Ref: 147
26) When there are too many users on the same segment of a LAN, what can cause the network to slow to an unacceptable pace?
A) traffic
B) highways
C) busses
D) tableaus
Answer: A
Diff: 2 Page Ref: 148
27) Which of the following statements is most accurate?
A) A layer 2 switch recognizes only its own network. A router, however, recognizes different networks by their addresses.
B) A layer 3 switch recognizes only its own network. A router, however, recognizes different networks by their addresses.
C) A layer 4 switch recognizes only its own network. A router, however, recognizes different networks by their addresses.
D) A layer 5 switch recognizes only its own network. A router, however, recognizes different networks by their addresses.
Answer: A
Diff: 3 Page Ref: 148
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28) Because of NOS's server focus, some networking professionals refer to a NOS as a ________.
A) hired helper
B) server operating system (SOS)
C) maidservant
D) house runner
Answer: B
Diff: 3 Page Ref: 149
29) How complex the user ID and password are, how frequently user passwords must be changed, and how user IDs and passwords are created, maintained, and distributed are based on
A) subscription policies
B) resolvers
C) network administration policies
D) message administration
Answer: C
Diff: 1 Page Ref: 149
30) A ________ license is one whereby the server is programmed to count how many users are currently using a given product.
A) metered
B) site
C) message
D) quotient
Answer: A
Diff: 1 Page Ref: 149
31) A ________ license covers the entire site so that anyone validated by the network can access the application as needed.
A) quality
B) quotient
C) metered
D) site
Answer: D
Diff: 2 Page Ref: 149
32) Which of the following statements is most accurate?
A) If a business primarily makes use of high-end, picture-driven types of data applications, then bandwidth and throughput requirements will be far less demanding.
B) If a business primarily makes use of low-end, text-driven types of data applications, then bandwidth and throughput requirements will be more difficult to use.
C) If a business primarily makes use of low-end, text-driven types of data applications, then bandwidth and throughput requirements will be highly demanding.
D) If a business primarily makes use of low-end, text-driven types of data applications, then bandwidth and throughput requirements will be far less demanding.
Answer: D
Diff: 3 Page Ref: 150
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33) Connecting all of the LANs of an organization entails another type of network called ________.
A) a backbone network (BN)
B) a Domain Name System
C) a freecard network
D) a gap-filled method
Answer: A
Diff: 3 Page Ref: 151
34) MAN stands for ________.
A) metropolitan area network
B) middle access node
C) mezza-and-nowidth
D) manned action network
Answer: A
Diff: 1 Page Ref: 151
35) The IEEE's initial standard for Gigabit Ethernet is ________.
A) open
B) XXZ
C) 802.3z
D) 145.4o
Answer: C
Diff: 1 Page Ref: 153
36) What are the two most common BN architectures?
A) open and closed
B) distributed and collapsed
C) long and short
D) vocal and silent
Answer: B
Diff: 2 Page Ref: 154
37) A ________ backbone is one that runs throughout the entire enterprise.
A) uniform
B) distributed
C) connected
D) header
Answer: B
Diff: 2 Page Ref: 154
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38) What kind of backbone connects all of the network segments to a central, single router or switch?
A) collapsed
B) open
C) crooked
D) distributed
Answer: A
Diff: 3 Page Ref: 156
39) A ________ is an internal, high-speed communications bus that is used in place of the connecting cables found in a distributed backbone.
A) frontjet
B) backplane
C) sidebus
D) middlecar
Answer: B
Diff: 2 Page Ref: 156
40) Which of the following is the most accurate statement?
A) A major disadvantage of a collapsed backbone configuration is that internetwork traffic has to pass through only one device, usually a router, on its way to its final destination.
B) A major advantage of an opened backbone configuration is that internetwork traffic has to pass through only one device, usually a router, on its way to its final destination.
C) A major disadvantage of a crooked backbone configuration is that internetwork traffic has to pass through only one device, usually a router, on its way to its final destination.
D) A major advantage of a collapsed backbone configuration is that internetwork traffic has to pass through only one device, usually a router, on its way to its final destination.
Answer: D
Diff: 2 Page Ref: 157
41) A ________ is a centralized wiring point or location for organizing and connecting networked devices, in particular, swithches and routers.
A) pocket
B) patch
C) ragged
D) hub
Answer: B
Diff: 2 Page Ref: 160
42) A Fast Ethernet segment can be no more than ________ long.
A) 2,500 meters
B) 25 meters
C) 25 centimeters
D) 250 meters
Answer: D
Diff: 2 Page Ref: 160
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43) Three types of topologies are ________.
A) diamond, neck, and car
B) circular, equivalent, and rock
C) star, ring, and bus
D) walled, vertical, and horizontal
Answer: C
Diff: 2 Page Ref: 162
44) The bus topology is ________ topology.
A) contention-based
B) vertical-based
C) driving-based
D) circular-based
Answer: A
Diff: 1 Page Ref: 162
45) Factors to consider when choosing a NIC include ________.
A) initials and standards
B) emergency protocol
C) bus width and memory capabilities
D) sirens and sound capabilities
Answer: C
Diff: 3 Page Ref: 163
46) In a TCP/IP LAN, client devices are referred to as ________.
A) systems
B) hosts
C) headers
D) patents
Answer: B
Diff: 3 Page Ref: 163
47) What is the term used for the capability of a technology to recover in the event of error, failure, or some other unexpected event that disrupts smooth organizational communications?
A) backup plan
B) emergency protocol
C) backplan
D) fault tolerance
Answer: D
Diff: 2 Page Ref: 163
48) A ________ is simply a means of extending the diameter, or distance, of the LAN.
A) hub
B) meeter
C) meter
D) bus
Answer: A
Diff: 3 Page Ref: 166
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49) In a 10Base T type of Ethernet LAN, the "10" stands for 10 Mbps, the "Base" represents baseband, and the "T" stands for ________.
A) twice
B) twisted-wire pair
C) tellpoint
D) true
Answer: B
Diff: 3 Page Ref: 166
50) The maximum end-to-end LAN diameter of 10BaseT Ethernet is ________ meters.
A) 2,500
B) 12
C) 25
D) 250
Answer: A
Diff: 2 Page Ref: 166
8.2 True/False Questions
1) Physical LAN components include NICs, client devices, servers, printers, cables, hubs, switches, and routers.
Answer: TRUE
Diff: 1 Page Ref: 140
2) Logical LAN components typically include device drivers, network operating systems, and desktop operating systems, as well as software that can be used to monitor, troubleshoot, and evaluate the performance of a LAN.
Answer: TRUE
Diff: 3 Page Ref: 140
3) Troubleshooting tools must always be software-based.
Answer: FALSE
Diff: 2 Page Ref: 140
4) Logical components, unlike physical components, do not need to be installed, configured, and maintained.
Answer: FALSE
Diff: 1 Page Ref: 140
5) Physical components are frequently referred to as hardware.
Answer: TRUE
Diff: 2 Page Ref: 140
6) Software is a set of programmed instructions that tell a device how to perform its functions.
Answer: TRUE
Diff: 3 Page Ref: 141
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7) Ethernet and variations of it are by far the most commonly deployed topology in LANs today.
Answer: TRUE
Diff: 1 Page Ref: 142
8) Classic Ethernet is a bus topology.
Answer: TRUE
Diff: 2 Page Ref: 142
9) The protocol most often associated with the bus topology is ring.
Answer: FALSE
Diff: 1 Page Ref: 143
10) CSMA/CD stands for Carrier Sense Multiple Access/Collision Detection.
Answer: TRUE
Diff: 2 Page Ref: 143
11) A physical address is an address that is specific, unique, and assigned to several NICs.
Answer: FALSE
Diff: 3 Page Ref: 143
12) If two or more NICs have the same physical address, communication is better.
Answer: FALSE
Diff: 1 Page Ref: 144
13) Typically, the larger the cache, the better the performance of the NIC.
Answer: TRUE
Diff: 3 Page Ref: 144
14) CPU stands for central processing unit.
Answer: TRUE
Diff: 1 Page Ref: 144
15) Gigabit Ethernet adapters can support up to 1 Gbps (billion bits per second) or 1000 Mbps.
Answer: TRUE
Diff: 3 Page Ref: 144
16) An Ethernet NIC address consists of 48 bits composed of 12 hexadecimal digits.
Answer: TRUE
Diff: 2 Page Ref: 145
17) Hexadecimal, or hex, is the Base-16 numbering system, and it uses the values 0 through 9 and the capital letters A through F.
Answer: TRUE
Diff: 1 Page Ref: 145
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18) The first six hex digits specify the interface serial number. The last six hex digits specify the NIC's manufacturer.
Answer: FALSE
Diff: 1 Page Ref: 146
19) Device drivers are software programs that control the NIC and allow it to work in association with the host device's network operating system.
Answer: TRUE
Diff: 2 Page Ref: 146
20) Media is plural, and medium is singular.
Answer: TRUE
Diff: 3 Page Ref: 147
21) The most common LAN medium is unshielded twisted-wire pair (UTP).
Answer: TRUE
Diff: 2 Page Ref: 147
22) Network wiring usually runs from all connected devices to a communications wiring closet.
Answer: TRUE
Diff: 3 Page Ref: 145
23) LAN resources can include, among other things, printers, applications, data, information, files, databases, security services, directory services, modems, Web hosting, and e-mail–basically anything that a group of users would need to have access to.
Answer: TRUE
Diff: 1 Page Ref: 146
24) In a TCP/IP LAN, networked devices, like clients, are referred to as hosts.
Answer: TRUE
Diff: 2 Page Ref: 147
25) With a peer-to-peer LAN, a specialized server operating system is required.
Answer: FALSE
Diff: 2 Page Ref: 147
26) Because a router uses addressing tables, it uses broadcast packets.
Answer: FALSE
Diff: 1 Page Ref: 148
27) A metered license is one whereby the server is programmed to count how many users are currently using a given product.
Answer: TRUE
Diff: 3 Page Ref: 149
28) The two most common BN architectures are distributed and collapsed.
Answer: TRUE
Diff: 2 Page Ref: 154
Copyright © 2014 Pearson Education, Inc.
29) A backplane is an internal, high-speed communications bus that is used in place of the connecting cables found in a distributed backbone.
Answer: TRUE
Diff: 1 Page Ref: 156
30) A disadvantage of a distributed backbone is that the type of cabling used may not support long distances between networks and backbone.
Answer: TRUE
Diff: 2 Page Ref: 170
31) Fault tolerance is the capability of a technology to recover in the event of error, failure, or some other unexpected event that disrupts organizational communications and functions.
Answer: TRUE
Diff: 3 Page Ref: 158
32) The patch panel can be a hub, switch, or router.
Answer: FALSE
Diff: 2 Page Ref: 160
33) A standard Ethernet segment may be up to 2,500 meters, whereas a Fast Ethernet segment can be no more than 250 meters.
Answer: TRUE
Diff: 3 Page Ref: 160
34) Placing the wiring closets in vertical alignment greatly facilitates their connection.
Answer: TRUE
Diff: 3 Page Ref: 161
35) An additional element in a LAN that has both physical and logical characteristics is the LAN's topology.
Answer: TRUE
Diff: 2 Page Ref: 162
36) The bus topology is not a contention-based topology.
Answer: FALSE
Diff: 1 Page Ref: 162
37) Switches are often associated with the data link layer, or layer 2. Routers are associated with the network layer, or layer 3.
Answer: TRUE
Diff: 3 Page Ref: 163
38) The smallest Ethernet frame possible is 64 bytes, or 512 bits.
Answer: TRUE
Diff: 2 Page Ref: 166
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39) Hubs can extend the diameter, or distance, of a LAN.
Answer: TRUE
Diff: 3 Page Ref: 167
40) Hubs create independent, dedicated circuits for the devices that are attached to them.
Answer: TRUE
Diff: 3 Page Ref: 167
8.3 Essay Questions
1) Explain the type of information that documentation of a LAN should be able to tell you.
Answer: Documentation needs to be current, accurate, and reliable. Your documentation should be able to tell you such things as what types of NICs you are using and where; the names, locations, and addresses of all your hubs, switches, routers, and servers; the status of your licensing for the server operating system and client applications; where and what types of printers you have; how users are granted or denied login user IDs and passwords; when and how backups are performed; who is responsible for administration of each part of the network; and so on.
Diff: 3 Page Ref: 139
2) Briefly describe what a topology is and what the three major topologies are.
Answer: Topologies determine not only how devices are connected to each other, but also how they access the media they use for communication. A topology is both physical and logical. A traditional star topology is configured such that a central controlling device has other networked devices connected to it by point-to-point circuits. A ring topology uses a single cable such that the cable ends meet and form a closed loop. IBM also introduced the token ring protocol, which is associated with the ring topology. The bus topology, like the ring, views its circuit as a single cable. Unlike the ring, the cable does not form a closed loop. Devices connect to the central cable, using it as a communications pipeline. The protocol most often associated with the bus topology is Ethernet.
Diff: 2 Page Ref: 141
3) What is a NIC, and how does it work?
Answer: An essential hardware component that each device on a LAN must have in order to communicate is a Network Interface Card, or NIC (pronounced nick). A NIC is also known as an adapter card. As you now know, each NIC has a physical MAC layer address. A physical address is an address that is specific, unique, and assigned to one and only one NIC. A NIC's physical address is, in fact, part of the card's physical manufacture. Therefore, if two or more NICs have the same physical address, communication problems will occur. It is possible in the manufacturing process that two NICs could erroneously be assigned the same physical address. In such an event, one of the two NICs would have to be replaced. In a TCP/IP network, any device, regardless of its type, that is connected to the network is referred to as a host. A host might be a client machine, a server, a printer, or any other type of device connected to the network. That host, however, must have a NIC that allows it to communicate on the network.
Diff: 3 Page Ref: 143
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The importance of this invention can hardly be overestimated. It ranks with Maudslay’s slide-rest and the turret tool-holder, as it is an essential feature in all modern automatic lathes, both for bar-stock and chucking work.
Assured of the success of the machine, Spencer withdrew from active connection with the Billings & Spencer Company in 1874, and in 1876, with George A. Fairfield, then superintendent of the Weed Sewing Machine Company, and others, formed the Hartford Machine Screw Company, one of the most successful enterprises in the city. Unfortunately, Mr Spencer withdrew in 1882 to manufacture a new repeating shotgun and rifle which he had invented. The gun was a success mechanically, but the Spencer Arms Company, which had been formed in 1883 at Windsor, Conn., was a failure, and Mr. Spencer lost heavily. In his later years Mr. Spencer has returned to the field where he did his most brilliant work, automatic lathes. He represents the New England mechanic at his best, and his tireless and productive ingenuity has made a permanent impress on modern manufacturing methods.
Francis A. Pratt was born at Woodstock, Vt. When he was eight years old his family moved to Lowell. He was a mechanic from boyhood but he had the good fortune to be apprenticed as a machinist with Warren Aldrich, a good mechanic and a wise teacher. At twenty, Mr. Pratt went to Gloucester, N. J., where he was employed first as a journeyman, later as a contractor. In 1852 he came to the Colt shop, where he worked for two years. He then accepted the foremanship of the Phœnix Iron Works, which was run by Levi Lincoln and his two sons.
Amos Whitney was born in Maine and moved to Lawrence, Mass., where he served his apprenticeship with the Essex Machine Company which built cotton machinery, locomotives and machine tools. He came from a family of mechanics. His father was a locksmith and machinist, his grandfather was an expert blacksmith, his great-grandfather was a small manufacturer of agricultural tools, and he is of the same family as Eli Whitney of New Haven, and Baxter D. Whitney, the veteran tool builder of Winchendon. In 1850 both he and his father were working at Colt’s factory at Hartford. In 1854 Amos Whitney joined Pratt in the Phœnix Iron Works, where
they worked together for ten years, the former as a contractor, the latter as superintendent. Whitney was earning over eight dollars a day when he left Colt’s and took up the new contract work which offered at the beginning only two dollars a day.
Many of the shops of that generation were “contract shops.” The Colt Armory was run on that basis, at least in its manufacturing departments. Under this system the firm or company furnished all the materials, machinery, tools, shop room and supplies, while the workmen were employed by the contractor, their wages being paid by the firm but charged against the contractor’s account. A better training for future manufacturers could hardly be devised, and a surprising number of these old-time contractors have succeeded later in business for themselves.
In the summer of 1860 Pratt and Whitney rented a small room and, in addition to their regular employment, began doing work on their own account, i.e., manufacturing the small winder for the Willimantic Linen Company. Mr. Whitney’s father-in-law acted as pattern maker, millwright, bookkeeper and general utility man. The following February they were burned out, but were running again a month later in other quarters. Here they continued to spread from room to room until all available space was outgrown. They succeeded from the very start, and at once became leaders and teachers of other mechanics, suggesters of new methods of work and of new means for its accomplishment. Both Pratt and Whitney were thoroughly familiar with gun manufacture, and the business was hardly started when the outbreak of the Civil War gave them more than they could do. In 1862 they took into partnership Monroe Stannard of New Britain, each of the three contributing $1200. Mr. Stannard took charge of the shop, as Pratt and Whitney were still with the Phœnix Iron Works. Within two years the business had increased to such an extent that they gave up their positions at the Phœnix works and in 1865 erected the first building on their present site. From $3600 in 1862 their net assets grew in four years to $75,000, and during the three years following that they earned and put back into the business more than $100,000. In 1869 the Pratt & Whitney Company was formed with a capital of $350,000, later increased to $500,000. In 1893 it was reorganized with a
capitalization of $3,000,000. Since that time it has become a part of the Niles-Bement-Pond Company.
Beginning with the manufacture of machine tools and tools for making guns and sewing machines, they have extended their lines until their catalog fills hundreds of pages. From their wide experience in interchangeable manufacture, it was natural that they should take a prominent part in developing the machinery for the manufacture of bicycles and typewriters, when, later, these were introduced.
Soon after the Franco-Prussian War, an agent of the company visited Prussia and found the royal and private gun factories equipped with old and inferior machinery and the armories bare. Mr. Pratt was sent for, and returned to Hartford with orders from the German Government for $350,000 worth of gun machinery. During the next few years Mr. Pratt made no less than ten trips to Europe, taking orders aggregating over $2,000,000 worth of machinery. When the panic of 1873 prostrated the industries of the United States, Pratt & Whitney had orders, mostly foreign, which kept them busy until 1875. Their equipment of the three royal armories of Spandau, Erfurt and Danzig resulted in an improvement in quality of output and a saving of 50 per cent in wages. Pratt & Whitney’s production of gun-making machinery alone has run into many millions of dollars, and there are few governments which have not at one time or another purchased from them.
Pratt & Whitney from the start were leaders in establishing standards, particularly in screw threads. Their gauges for pipe threads have for years been the standard for the country The troubles which arose from the lack of agreement of standard gauges and the growing demand for interchangeable bolts and nuts led to a demand on the company for a set of gauges upon which all could agree.
In undertaking this work Pratt & Whitney examined their own standards of length with reference to government and other standards in this country and abroad. The results were conflicting and very unsatisfactory. By different measurements the same bar would be reported as above and as below the standard length, and the investigation produced no results which could be used for a working basis. At length Prof. William A. Rogers of Harvard
University, and George M. Bond, backed by the Pratt & Whitney Company, developed the Rogers-Bond comparator with which they determined the length of the standard foot. When they began, the length of the yard and its subdivisions varied with the number of yardsticks. Professor Rogers’ work was based on line measurement rather than the end measurement which had held sway from the time of Whitworth and which is now generally recognized to be inferior for final reference work. Professor Rogers went back of all the secondary standards to the Imperial Yard in London and the standard meter in the Archives at Paris. He obtained reliable transfers of these, and with the coöperation of the United States Coast Survey, the most delicate and exhaustive comparisons were made of the standard bars prepared by him for the use of the company with the government standard yard designated “Bronze No. 11.” Many thousands of dollars and three years of time went into this work.
The methods used and the results obtained were examined and reported upon by a committee of the American Society of Mechanical Engineers, and the conclusion given in their report is as follows:
The completion of the Rogers-Bond comparator marks a long stride in advance over any method hitherto in use for comparison and subdivision of line-measure standards, combining, as it does, all the approved methods of former observers with others original with the designers Comparisons can thus be checked thoroughly by different systems, so that the final result of the series may be relied on as being much nearer absolute accuracy than any hitherto produced
The calipering attachment to the comparator deserves special commendation, being simple in the extreme, and solving completely the problem of end measurements within the limit of accuracy attainable in line reading, by means of the microscope with the micrometer eye-piece. The standard to which the end measurements are referred is not touched, and each measurement is referred back to the same zero, so that error from end wear does not enter into the problem. This attachment is in advance of all hitherto known methods of comparing end measures, either with other end measures or with line standards, both as to rapidity of manipulation and accuracy of its readings, the strong point in its construction being that it refers all end measures to a carefully divided and investigated standard bar, which is not touched during its use, and cannot be in the slightest degree injured by this service, thus giving convincing assurance that the measures and gauges produced by its use will be accurate and interchangeable
In the opinion of this committee, the degree of accuracy already attained is such that no future improvements can occasion changes sufficiently great to affect the practical usefulness of the magnitudes here determined, or the interchangeability of structures based upon them with those involving further refinement
Prof W A Rogers and Mr George M Bond are unquestionably entitled to great credit for the admirable manner in which they have solved the problem of exact and uniform measurement, while the enterprise of the Pratt & Whitney Company in bringing the whole matter into practical shape, is deserving of the thanks of the engineering community [183]
[183] Those interested may find detailed descriptions of the methods used and of the Rogers-Bond comparator in the following references: George M Bond: Paper on “Standard Measurements,” Trans A S M E , Vol II, p 80 George M Bond: Paper on “A Standard Gauge System,” Trans A S M E , Vol III, p 122 Report of Committee on Standards and Gauges, Trans A S M E , Vol IV, p 21 (quoted above) W A Rogers: Paper, “On a Practical Solution of the Perfect Screw Problem,” Trans. A. S. M. E., Vol. V, p. 216. Two lectures delivered by George M. Bond before the Franklin Institute, Philadelphia, in 1884, on: 1. “Standards of Length and their Subdivision.” 2. “Standards of Length as Applied to Gauge Dimensions.”
The standards so obtained became the basis of the gauges which Pratt & Whitney have produced.
In 1888 the company received its first order for Hotchkiss revolving cannon, and for three- and six-pounders rapid-fire guns. They have made hundreds of these guns for the secondary batteries of war vessels. In 1895 they brought out a one-pounder invented by E. G. Parkhurst, an expert mechanic, who had entered their employment as assistant superintendent in 1869 and later took charge of their gun department.
For many years the Pratt & Whitney tool-room lathes were the standard for the country. Later their leadership was materially affected by the Hendey Machine Company of Torrington, Conn., who built a high grade tool-room lathe having the change-gear box which has since been applied to nearly all types of machine tools. The change-gear box is one of the important contributions to tool building made in recent years. Among the later developments introduced by Pratt & Whitney is the process of thread milling, and they have designed a full line of machines for this work.
The Pratt & Whitney works, like the Colt Armory, has been a training school for successful tool builders. Worcester R. Warner and Ambrose Swasey were both foremen at Pratt & Whitney’s and left there to go west, first to Chicago and then to Cleveland. Some account of these two men will be given in a later chapter. Pratt & Whitney have had a marked influence on tool building in Cleveland, for, in addition to Warner and Swasey, E. C. Henn and Hakewessel of the National Acme Manufacturing Company who developed the multi-spindle automatic lathe, A. F. Foote of Foote, Burt & Company, and George C. Bardons of Bardons & Oliver, come from their shop. Johnston of Potter & Johnston, Pawtucket, was chief draftsman at Pratt & Whitney’s; and J. N. Lapointe who later developed the broaching machine, Dudley Seymour of Chicago, Gleason of the Gleason Works in Rochester, E. P. Bullard of Bridgeport, and F. N. Gardner of Beloit, Wis., inventor of the Gardner grinder, were all workmen there.
Mr. Gleason was also a workman in the Colt Armory. He went to Rochester in 1865 and the works which he developed form the most important tool building interest in western New York. There have been “a good many starts there in tool building and almost as many finishes.” Mr. Gleason always said that but for the training and methods he had gained at Hartford he would have shared their fate. Like many others, his company began with a general line of machine tools but has come to specialize on one type of machine, bevel-gear cutters, of which they build a most refined type.
E. P. Bullard, like Gleason, worked at both Colt’s and Pratt & Whitney’s. Later he formed a partnership with J. H. Prest and William Parsons, manufacturing millwork and “all kinds of tools” in Hartford. In 1866 he organized the Norwalk Iron Works Company of Norwalk, but afterwards withdrew and continued the business in Hartford. For a number of years Mr. Bullard was in the South and Middle West, at Athens, Ga., at Cincinnati, where he organized the machine tool department of Post & Company, and at Columbus, where he was superintendent of the Gill Car Works. In 1875 he established a machinery business in Beekman Street, New York, under the firm name of Allis, Bullard & Company. Mr. Allis withdrew in 1877 and the Bullard Machine Company was organized. Recognizing a demand
for a high grade lathe he went to Bridgeport, Conn., and engaged A. D. Laws to manufacture lathes of his design, agreeing to take his entire output. In the latter part of the same year Mr. Bullard took over the business and it became the Bridgeport Machine Tool Works. In 1883 he designed his first vertical boring and turning mill, a single head, belt feed machine of 37 inches capacity. This is believed to be the first small boring machine designed to do the accurate work previously performed on the face plate of a lathe. Up to that time boring machines were relied on only for large and rough work. In 1889 he transferred his New York connections to J. J. McCabe and gave his entire attention to manufacturing, the business being incorporated as the Bullard Machine Tool Company in 1894.
The building of boring mills gradually crowded out the lathes, and for twenty years the company has concentrated on the boring machine as a specialty. In their hands it has received a remarkable development. They introduced a range of small-sized mills capable of much more accurate work than had been done on this type of machine. They applied the turret principle to the head carried on the cross rail and a few years later introduced a mill having a head carried on the side of the frame which permitted of the close working of the tools. These improvements transformed the boring mill into a manufacturing machine, and it became practically a vertical turret lathe with the advantages inherent in that type of machine. This trend toward the lathe type has finally resulted in a multiple stationtype of machine which is in effect a vertical multi-spindle automatic chucking lathe with five independent tool heads, as shown in Fig. 56. Comparison of this with Fig. 15, shows how the lathe has developed in the 115 years since Maudslay introduced the slide-rest principle and the lead screw.
