Term
| Infrastructure Wireless Networks |
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Definition
| The MU(Mobile Unit) connects to a router which is connected to the internet |
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Term
| Infrastructure-less Wireless Networks |
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Definition
| (Ad Hoc Wireless Networks) MU's connect to each other |
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Term
| Infrastructure-less advantages and diss |
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Definition
Adv-set up anywhere
Diss- security, bandwidth, power, |
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Term
Caching Model
Size& weight
Cost
BW
Computations
Disconnection |
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Definition
| good +computation and no +disconnections |
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Term
Remote access model
Size& weight
Cost
BW
Computations
Disconnection |
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Definition
Terminal
+size & weight
+BW
+Cost |
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Term
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Definition
| uses a cache to anwser the queries. uses IR to validate cache |
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Term
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Definition
| goes through the server every time there is a query |
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Term
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Definition
servers know what MU's have in the cache
Disadvantages:
a. If the client is disconnected the server is unable to track it.
b. Waste of bandwidth – The client gets notified regardless of
whether he needs a data item or not. |
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Term
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Definition
server doesnt know the state of the MUs cache.
Broadcasting IR sunchronously which uses bandwidth but not as much as statefull server |
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Term
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Definition
| Introductions reordering by modifying code to deal with power consumption |
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Term
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Definition
| you can quadraticaly reduce the power by dropping the voltage in the consumed power equation of c*f*v^2 |
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Term
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Definition
| Has broacasting stamps when the reports an item was modified in the time period of L |
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Term
| Why is caching important? |
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Definition
| Reduces contention on the wireless channel. |
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Term
| How do we manage the MU caches? |
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Definition
| Stateful and stateless servers |
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Term
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Definition
The server broadcasts information about
the items that changed in the last w
seconds.
The timestamps of the latest changes for
the changed items are included in the
reports.It uses synchronous, history based and
uncompressed reports |
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Term
| What consumes most power in logic |
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Definition
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Term
| Ways to power with the clock |
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Definition
no clock
Less clock
slow clock |
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Term
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Definition
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Term
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Definition
clock gating(turning on and off)
Globally Asynchronous
Locally Synchronous
(GALS) |
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Term
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Definition
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Term
| mapping techniques(MM to Cache) |
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Definition
direct
full associative
set associative |
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Term
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Definition
MM to cache have same block
dissadvantage- high miss rate
adv- simple, cheap, easy to implement |
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Term
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Definition
cache= mm
+ miss rate,
- complex, costly
-access is slow |
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Term
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Definition
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Term
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Definition
| break a step down into smaller instructions such as {fetch,decode,execute} into {fetch}{decode}{execute} |
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Term
| What to do with a stalling pipeline |
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Definition
| gate it or add branch prediction |
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Term
| PaOS Tasks - Disk Scheduling |
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Definition
-Save power by spinning down when idle
-Spin-up on request
adv- saves power if not constaly using disk
diss- pin up and down cost power and is slower accessing time |
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Term
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Definition
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Term
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Definition
IR broadcasted immediately
after changes to the data items occur.
Disadvantages:
A disconnected client upon awake has to wait for an
unspecified amount of time to get an update. |
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Term
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Definition
Periodic broadcasts.
Disadvantages:
More network traffic even there are no/less updates |
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Term
| Broadcasting Time-stamps algo |
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Definition
If Ti - Tj > w 1. Drop the entire cache.
If Ti – Tj <= w :For every item (k) in the cache,
compare the cached timestamp of the item (Ck) with
the timestamp of the last update of the item (Tk)
1. If Ck < Tk, then throw item k out of the cache.
else, then change Ck = Ti
If the item k is present in the cache, use
the cached value.
Else go uplink with the query and download K |
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Term
| Flash memory compared to hard disks |
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Definition
Adv- less latency, less power consumption, more reliable
Dis- limited size, limited number of writes you can do |
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Term
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Definition
The server sends information about the
items that changed since the last IR.
It uses synchronous, history based and
uncompressed reports |
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Term
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Definition
If Ti - Tj > L
1. Drop the entire cache
If Ti – Tj <= L : For every item (k) in the cache, if k
is in the report then through item k out of the cache.Finally, for every item k in the query:
If the item k is present in the cache, use
the cached value.
Else go uplink with the query (ask the
server to send the latest value of the it |
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Term
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Definition
Dissconnections ->0
Amnesic terminals are better |
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Term
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Definition
Dissconnections ->1
Time stamps are the best |
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