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Tara2
Posted: Tuesday, February 23, 2021 7:13:41 AM

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Joined: 11/8/2017
Posts: 3,400
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In another forum they say 'scheme' isn't a proper word here but 'mechanism' is, do you think so?


Two different deadlock-prevention schemes using timestamps have been proposed:

1. The wait–die scheme is a nonpreemptive technique.When transaction Ti requests a data item currently held by Tj, Ti is allowed to wait only if it has a timestamp smaller than that of Tj (i.e., Ti is older than Tj). Otherwise, Ti is rolled back (dies). For example, suppose that transactions T14, T15, and T16 have timestamps 5, 10, and 15, respectively. If T14 requests a data item held by T15, then T14 will wait. If T16 requests a data item held by T15, then T16 will be rolled back.
2. The wound–wait scheme is a preemptive technique. ....

The major problem with both of these schemes is that unnecessary rollbacks may occur.

Hence, the timeout-based scheme has limited applicability.
BobShilling
Posted: Tuesday, February 23, 2021 7:18:26 AM
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Joined: 4/1/2018
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Location: Beroun, Stredocesky, Czech Republic
Tara2 wrote:
In another forum they say 'scheme' isn't a proper word here but 'mechanism' is, do you think so?.


That isn't a totally accurate picture of what was said here: https://forum.wordreference.com/threads/mechanism-scheme.3797255/#post-19393025
Wilmar (USA) 1M
Posted: Tuesday, February 23, 2021 7:29:38 AM

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Location: Vinton, Iowa, United States
You need to be careful where you are gathering your "facts". The site you reference is only a general purpose forum. There is no expectation of expertise in the area of computing from anyone posting there. People with a strong background in computer engineering can explain the use of that vocabulary -- not the general population.
Tara2
Posted: Tuesday, February 23, 2021 8:24:29 AM

Rank: Advanced Member

Joined: 11/8/2017
Posts: 3,400
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Wilmar (USA) 1M wrote:
You need to be careful where you are gathering your "facts". The site you reference is only a general purpose forum. There is no expectation of expertise in the area of computing from anyone posting there. People with a strong background in computer engineering can explain the use of that vocabulary -- not the general population.

Yes, many thanks dear Wilmar!!!
FounDit
Posted: Tuesday, February 23, 2021 10:52:14 AM

Rank: Advanced Member

Joined: 9/19/2011
Posts: 15,184
Neurons: 72,704
Tara2 wrote:
In another forum they say 'scheme' isn't a proper word here but 'mechanism' is, do you think so?


Two different deadlock-prevention schemes using timestamps have been proposed:

1. The wait–die scheme is a nonpreemptive technique.When transaction Ti requests a data item currently held by Tj, Ti is allowed to wait only if it has a timestamp smaller than that of Tj (i.e., Ti is older than Tj). Otherwise, Ti is rolled back (dies). For example, suppose that transactions T14, T15, and T16 have timestamps 5, 10, and 15, respectively. If T14 requests a data item held by T15, then T14 will wait. If T16 requests a data item held by T15, then T16 will be rolled back.
2. The wound–wait scheme is a preemptive technique. ....

The major problem with both of these schemes is that unnecessary rollbacks may occur.

Hence, the timeout-based scheme has limited applicability.

A scheme is just a plan of action. However, over the years, it has been used more often when describing a sneaky, or evil, plan of action. Since it has been used so much for that meaning, this is the one most people think of when they see it.

In computing language, though, it should have the original meaning of a plan of action that includes certain steps that need to be taken. So for your purpose, or that of the material you are reading, scheme is fine.
Tara2
Posted: Tuesday, February 23, 2021 11:03:14 AM

Rank: Advanced Member

Joined: 11/8/2017
Posts: 3,400
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FounDit wrote:
Tara2 wrote:
In another forum they say 'scheme' isn't a proper word here but 'mechanism' is, do you think so?


Two different deadlock-prevention schemes using timestamps have been proposed:

1. The wait–die scheme is a nonpreemptive technique.When transaction Ti requests a data item currently held by Tj, Ti is allowed to wait only if it has a timestamp smaller than that of Tj (i.e., Ti is older than Tj). Otherwise, Ti is rolled back (dies). For example, suppose that transactions T14, T15, and T16 have timestamps 5, 10, and 15, respectively. If T14 requests a data item held by T15, then T14 will wait. If T16 requests a data item held by T15, then T16 will be rolled back.
2. The wound–wait scheme is a preemptive technique. ....

The major problem with both of these schemes is that unnecessary rollbacks may occur.

Hence, the timeout-based scheme has limited applicability.

A scheme is just a plan of action. However, over the years, it has been used more often when describing a sneaky, or evil, plan of action. Since it has been used so much for that meaning, this is the one most people think of when they see it.

In computing language, though, it should have the original meaning of a plan of action that includes certain steps that need to be taken. So for your purpose, or that of the material you are reading, scheme is fine.

Many thanks dear FounDit for the great explanation!!!, I still have two questions:
1- What do you mean by 'However, over the years, it has been used more often when describing a sneaky, or evil, plan of action', please?
2- Is 'mechanism' correct here two, please?
FounDit
Posted: Tuesday, February 23, 2021 11:25:31 AM

Rank: Advanced Member

Joined: 9/19/2011
Posts: 15,184
Neurons: 72,704
Tara2 wrote:
FounDit wrote:
Tara2 wrote:
In another forum they say 'scheme' isn't a proper word here but 'mechanism' is, do you think so?


Two different deadlock-prevention schemes using timestamps have been proposed:

1. The wait–die scheme is a nonpreemptive technique.When transaction Ti requests a data item currently held by Tj, Ti is allowed to wait only if it has a timestamp smaller than that of Tj (i.e., Ti is older than Tj). Otherwise, Ti is rolled back (dies). For example, suppose that transactions T14, T15, and T16 have timestamps 5, 10, and 15, respectively. If T14 requests a data item held by T15, then T14 will wait. If T16 requests a data item held by T15, then T16 will be rolled back.
2. The wound–wait scheme is a preemptive technique. ....

The major problem with both of these schemes is that unnecessary rollbacks may occur.

Hence, the timeout-based scheme has limited applicability.

A scheme is just a plan of action. However, over the years, it has been used more often when describing a sneaky, or evil, plan of action. Since it has been used so much for that meaning, this is the one most people think of when they see it.

In computing language, though, it should have the original meaning of a plan of action that includes certain steps that need to be taken. So for your purpose, or that of the material you are reading, scheme is fine.

Many thanks dear FounDit for the great explanation!!!, I still have two questions:
1- What do you mean by 'However, over the years, it has been used more often when describing a sneaky, or evil, plan of action', please?
In a great many books and movies, the antagonists are almost always described as "scheming" to do something, to have an evil scheme. Sometimes it is described as a scheming plot, or a scheme to kidnap, but almost always, it is the evil people who scheme. You never hear the good guys said to be scheming, or wanting to scheme. It's just the way the word has developed in modern use. I'd bet if you ask most natives what they think of scheme, they'd say it is not a good thing, even though it simply means "a plan".

2- Is 'mechanism' correct here two, please?
I'd say, yes. A mechanism is a machine that does its work through steps, or actions. In the same way, a scheme is a plan of action that accomplishes the desired goal through a series of steps or actions. So in that regard, both work. It is, again, a way of speaking of a computer program in different language where the instructions are compared to the parts of a machine. So a program is both a scheme (a plan), and like a machine (a mechanism). Both do their work through a series of steps, or actions.
Tara2
Posted: Wednesday, February 24, 2021 9:10:20 AM

Rank: Advanced Member

Joined: 11/8/2017
Posts: 3,400
Neurons: 12,458
Many thanks dear FounDit for the great explanation!!!
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