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6.1.4

Describe the possible problems resulting from the limitations in the resources in a computer system.

 

Teaching Note:

For example, user time wasted if the primary memory is too small or processor speed inadequate.

Multi-access and multi-programming environments should be considered as well as single-user systems.

Sad Mac Icon
(By The original uploader was Mysid at English Wikipedia - Public Domain)

 

Sample Question:

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JSR Notes:

Also refer to 6.1.3 for a general discussion of the limitations of various resources within computer systems.

 

First, the second part of the Teaching Note - multi-access, and multi-programming environments and single-user systems

Teaching Note Part 2 Definitions

Single user system: By this, we simply mean a regular PC or laptop or phone that is used by one person at a time. As with a shared family computer, several people may regularly use it, but it is not intended that they do so at the same time. So in terms of various system resources, whether it be RAM or network access or cache, no more is needed than that to satisfy one user.

Multi-access (multi-user) Environment: By this, we mean more than one user is accessing the system in question at one time. In the early days of computing this is the way just about everybody using computers had access, usually at a university or large government agency, in which they used a "thin client" or "dumb terminal" attached to a mainframe computer through a local area network. All the terminal was was a monitor and a keyboard; all the processing was done at the mainframe.

For such a system, be it a mainframe, or a server/client system, obviously certain features are of greater importance, notably the network capacity and resources, and almost certainly huge amounts of RAM and storage, and processing capabilities. The operating system also has to support multi-access; examples include Linux and UNIX. The OS has to be able to juggle many user requests at the same time, particularly for use of shared resources that work in a serial nature, such as printers; one job has to be finished before the next starts, and so the OS manages a queue.

One major advantage of a multi-user system is expensive hardware and software can be shared, so the cost per user can be actually reasonable. That said, the hardware and software is more expensive, simply by the massive amounts of RAM and storage and processing power needed, so a certain number of users are required for it to make economic sense.

Multi-programming Environment: By this we mean any system which can seem to be running more than one program at the same time. This is not parallel processing (such as that which is possible with multiple core computers, or seemingly possible with hyper-threading). PCs have been able to do this for years; simply having Chrome and Word open at the same time is an example. Assisted by the operating system, the device is able to switch back and forth between two running programs. More and more smaller devices like smart phones are also able to do this. (And I'm not sure where this fits in other than this in 2018.)

 

 

For this, we will drop "sub-laptops", and replace them with tablets, and also drop PDAs, which have been replaced by smart phones.

And, with this, do focus on what distinguishes each category from the other, both in terms of it's power/advantages, and also the limits which are most likely to affect it.

 

Legend:

GREEN: The resources for each particular IT device which need to be most managed will be highlighted green.

AMBER: The resources that are highlighted amber are important depending on the use of the particular device.

 

 

Mainframes

Primary memory (RAM)

Built-in secondary storage (HD)

External Disk Storage Processor:
- # / cores,    - speed
- multitasking or not
Cache

32 - 512 GB

3TB RAIM (like RAID for hard drives, so there is redundancy; if one part of RAM fails, it is backed up.

conventional HD,
tape

tons

As much as possible; depends on number of drives.

Used for backup/redundancy

6 cores each 5 GHz, on up to max 120 cores

Very important is the way the mainframe is able to manage the potential vast amounts of cache.

64 KB L1 per core instruction cache
96 KB L1 per core data cache
1 MB L2 instruction & data cache
48 MB L3 cache RAM
384 MB L4 cache per 6 processors.

Limits & Problems Resulting from Reaching those Limits

       

Slow terminals when heavy usage.

Very important to know what maximum usage is...

Users expect the same speed as their PCs.

So, for example if only 32 GB, and 32 users connected at the same time, only 1 GB of memory for each.

It could fill up. -------

Users very limited in size of files, or may even not be able to upload files at all.

Frustration and problems with doing their jobs can result.

This too could fill up. -------

Likely this limit could be overcome with additional external storage added, but that costs money.

Processors could be "maxed out. -------

Slower processing for all connected to the mainframe, and so frustration and reduced work productivity.

For those operations requiring lots of repetitive operations, the cache could reach its limit. -------

Distinctly slower processing of such processes as multimedia rendering, particularly when many users using the same cache-intensive application.

Mainframes cont.

Network Connectivity / Bandwidth

Graphics Processor

& Screen Resolution

Sound processor & Speaker

Relationship to the Cloud Power Consumption/Issues

limited by the network.

Number of in/out connections is important for number of terminals which can connect (64, for example)

Limited by the bus speed, which would be in the single Gigahertz, for example 8 GHz.

In and out...

like anything with a custom made server, if you want it you got it! Unnecessary

Does not upload to "The Cloud."

 

In fact, takes the place of "clouds". You could look at them as providing "mini" clouds limited to certain.

Consumes lots of electricity, and needs tons of air conditioning to keep cool.

Needs battery/generator power backup for cases of power outage.

But no battery issues per se.

Limits & Problems Resulting from Reaching those Limits      

Bandwidth the mainframe could be reached, or indeed the capacity of the network itself could reach its limit. -------

So no different issues than if users using PCs with limited bandwidth. Many on-line activities become almost impossible.

A question of how many connections possible at one time (is it via a switch, or directly to the server)

Graphics processors could be "maxed out". -------

Depends on work being done; but at a Arts or Multimedia/Game school for example, this becomes important, and limiting.

   

No issues as long as assured appropriate backup.

Though, since no regular battery cannot be used in times of electrical blackout.

If a blackout, people connected lose their work.

Servers

Primary memory

(RAM)

Built-in secondary storage (HD)

External Disk Storage Processor:
- # / cores,    - speed
- multitasking or not
Cache

Elsa Blade Server Example: 12 DIMM, Up to 192 GB, 48 DIMM, Up to 384 GB

School Example Intel Xeon E5-2620: 64 GB RAM

depends on use; if more for storage or for processing.

192 GB - 15 TB

Elsa Blade Server Example: 1.3 GHz, 1.1 GHz

School Ex. Intel Xeon E5-2620: RAID 1 - 300 GB

School Example Intel Xeon E5-2620: RAID 5 - 4 x 2 TB

Elsa Blade Server Example: # of cores: up to 24

Elsa Blade Server Example: 1 or 2 x 6MB shared Level 2 cache memory

Limits & Problems Resulting from Reaching those Limits        

Server's RAM fills up.------

All services offered by the server are slower, since virtual memory has to be used, which, using the HD is much slower.

An example would be a school's database is very slow to work with client-side.

HD fills up.-------

Not only will no more data be able to be saved to the server, but all server processing will be slower with a full hard drive.

Fills up.-------

This isn't such a big deal, as new/more external devices can quite easily be attached/installed.

But, this will cost money and inconvenience.

And while the issue persists, what to do with all the data? Possibly swap out older data, but this may be undesirable.

Processor-intensive activities - perhaps new software/services require more "umph" than the processors have. -------

This can cause slow delivery of services, and also risks causing freezes.

All clients will experience frustration, and the work flow and productivity of the organization will be hindered.

Cache filled up.-------

All processing of things that rely on large cache quantities will be severely slowed down. Notably all multimedia activities done by the server will be slower.

Servers cont.

Network Connectivity / Bandwidth

Graphics Processor

& Screen Resolution

Sound processor & Speaker

Relationship to the Cloud Power Consumption/Issues

Elsa Blade Server Example: Bandwidth: 7Tb/sec

Elsa Blade Server Example: Integrated ATI RN-50, 32 MB video memory

Elsa Blade Server Example:

Does not upload to "The Cloud."

 

Depending on how they are set up for mass storage they could take the place of "clouds". You could look at them as providing "mini" clouds limited to certain.

Consumes lots of electricity, and needs tons of air conditioning to keep cool.

Needs battery/generator power backup for cases of power outage.

But no battery issues per se.

Limits & Problems Resulting from Reaching those Limits      

Available bandwidth all taken up.-------

All data transfer and processing services offered by the server will be slower.

Frustration by clients results, along with decreased productivity.

Certain applications can't be run, due to inadequate graphics capabilities.-------

All graphics reliant services which depend on the limited applications cannot be run.

And even before such extreme limits are reached, any graphics processing will be slower.

N/A (At least, usually Not Applicable.)   No issues as long as assured appropriate backup. Though, since no regular battery cannot be used in times of electrical blackout.

 

PCs & Laptops

Primary memory

(RAM)

Built-in secondary storage (HD)

External Disk Storage Processor:
- # / cores,    - speed
- multitasking or not
Cache
~2-16 GB ~128 GB-1 TB   ~2-3 GHz ~2-3 GHz
Limits & Problems Resulting from Reaching those Limits        
The RAM can fill up, and therefore the computer will not be able to load as much of the applications into fast RAM, and end up using the slower Hard Drive for virtual memory. This slows down all applications.

The hard drive fills up.

The problems that result is that you cannot store any other files or install any other applications.

And there is no longer space for the HD to be used as virtual memory if needed.

Freezing possible at this point

The external hard drive fills up.

If it fills up you can no longer back up your files (for example via Time Machine.

Or cannot add more songs or videos or pictures to their external HD.

Don't have multiple processors or multi-cord processor, or fast processors or processor(s) capable of multitasking.

Problem is that everything done on that computer is slow, and some things just can't be done like opening large files, or do processing intensive tasks like 3d rendering, or exporting a movie from iMovie, and any conversion between file formats including compression.

There is less cache available to be used.

So less repetitive tasks can be speeded up.

Games like Starcraft and other strategy games do tons of similar kinds of processing, and so will be slower.

Many other processing situations which have repetitive things are slower.

PCs & Laptops cont. 

Network Connectivity / Bandwidth

Graphics Processor

& Screen Resolution

Sound processor & Speaker

Relationship to the Cloud Power Consumption/Issues
variable

Good graphics processor needed for multimedia and 3d rendering applications.

High resolution screens make a difference particularly on laptop screens since they are not that big.

 

Can upload to the cloud for storage, as new laptops with tiny hard drives are intended to do.

All PCs and laptops could use the cloud for backup, keeping in mind privacy issues.

PCs must be plugged in to an electricity source - they have no battery.

 

Laptops can be plugged in to an electricity source, but have a battery as well.

Limits & Problems Resulting from Reaching those Limits      

Slow Internet and network connectivity, like Suzi's old iMac.

(The machine itself cannot handle fast Internet connection.)

So slow things which are frustrating and almost impossible, such as all real time communication apps like Skype and Messenger. And any downloading like torrents takes forever

The graphics processor can't keep up with certain tasks, and the graphics memory starts to use system RAM, which has a much slower bandwidth.

Frame rates of games drop, or there is "stuttering" while playing SIMS is impossible and lags a lot.

And same with videos.

There just is no good quality sound from

Loud is easy, quality is hard, and there is "grey noise", random static sound, is in the background.

See network bandwidth. Laptop batteries that suck can be a real problem. Batteries losing charge can be big issue particularly when doing processor intensive tasks.

 

Netbooks

Primary memory

(RAM)

Built-in secondary storage

(HD)

External Disk Storage Processor:
- # / cores,    - speed
- multitasking or not
Cache
2 - 4 GB 16 GB SSD - 64

Have - USB & SD
Google Drive must be used by Chromebook & Chrome OS devices.

Intel Core i5 (1.8 GHz CPU) 1 MB
Limits & Problems Resulting from Reaching those Limits        
Once the RAM is filled up, the netbook will not load as much of the applications and will end up using the slower HD, this will slow down the device. The hard drive must be large. If it is not large enough for your files, the consumer must limit their file sizes and device will be slow. Inability to store lots of photos and movies if there is not a high capacity external disk available, since the hard drive of the notebook will likely be low capacity. If it is not fast, people will lose patience and could maybe lose files, or switch to another company If there is less cache, there is less repetitive tasks that can be processed therefore it may take longer and device will be slower.

Netbooks cont.

Network Connectivity / Bandwidth

Graphics Processor

& Screen Resolution

Sound processor & Speaker

Relationship to the Cloud Power Consumption/Issues
LTE, Bluetooth, WiFi Intel HD graphics 4000 GDU   If have small hard drives, might have to take advantage of cloud storage. Can be plugged in to an electricity source, but have a battery as well.
Limits & Problems Resulting from Reaching those Limits        
Slow Internet downloading will take a long time. “Will tend to be "lower end" graphics processor and not big screen resolution, so limiting to graphics work.” Limitation: anything from poor quality sound all the way to no sound. For videos and music the speaker should be able to work well. Cloud helps keep your information in a safe place, for long period of time (back-up) without this backup you might lose the important information on your device. Poor batteries which lose their charge quickly can be a big problem; possible loss of data, and definitely more "down time" where the notebook cannot be used.

 

Tablets

Primary memory

(RAM)

Built-in secondary storage (HD)

External Disk Storage Processor:
- # / cores,    - speed
- multitasking or not
Cache
256 MB - 1024 MB 16 - 128 GB 64 - 500 GB wireless Time Capsule. 1.3 GHz dual core L1: 128 KB
L2: 1 MB
L3: 4 MB
Limits & Problems Resulting from Reaching those Limits        
Slow. Can't load as many applications. Need to get external storage or delete files.   Slow games and multimedia and other things that repeat a lot of processing tasks. Can't load

Tablets cont.

Network Connectivity / Bandwidth

Graphics Processor

& Screen Resolution

Sound processor & Speaker

Relationship to the Cloud Power Consumption/Issues

WiFi, 3G and Cellular

Max. 15000 Kbps

PowerVR "quad core graphics"

Stereo & jack

20 Hz to 20 KHz

Since have limited storage, can use the cloud for this. Can be plugged in to an electricity source, but have a battery as well.
Limits & Problems Resulting from Reaching those Limits      
  Will tend to be "lower end" graphics processor and not big screen resolution, so limiting to graphics work.     Poor batteries which lose their charge quickly can be a big problem.
 

Cell Phones

(Assume below to be thinking about smart phones.)

Primary memory

(RAM)

Built-in secondary storage (HD)

External Disk Storage Processor:
- # / cores,    - speed
- multitasking or not
Cache
~1 - 2 GB ~16-32 GB   1 - 2, even quad-core
~ 1.3 GHz
- ~2.3 GHz
1 MB

Limits & Problems Resulting from Reaching those Limits

       

apps and apps switching are slower.

can't open as many (assuming multi-tasking)

Ex. prob. Loading of maps with alt-tabbing slow.

Lose GPS

"Phone storage: Run out of space for:

contacts
picture,
messages (In-box full)
can't download/try more apps.

games

If no SD card, can't add storage; dependent on out-of-the box storage.

(Refer to built-in storage issues.)

Slow accessing anything.

Gets stuck/freezes

Can't send a picture over texting - messes up format of image in the sending.

 

Cell Phones cont.

Network Connectivity / Bandwidth

Graphics Processor

& Screen Resolution

Sound processor & Speaker

Relationship to the Cloud Power Consumption/Issues

3G, or WiFi,
USB or WiFi, or Bluetooth to comp.

variable

Adreno

1.5 GHz

Up to HD for high end smart phones.

up to 44 KHz sound sample

decibel

Can use for storage and backup. A particularly good idea because cell phones can be easily lost. Run on a battery alone.

Limits & Problems Resulting from Reaching those Limits

 

 

 

2G vs 3G: Internet issue and slow access.

No WiFi is big problem, must always be paying for 3G services.

Need good graphics card and high resolution for watching video.

Horrible sound for calling/hearing conversations.

Speakers not good enough...

 

Poor batteries which lose their charge quickly can be a big problem.

The "smarter" the phone, and the more that it does, particularly real time and/or at the same time, like having WiFi enabled, the quicker the battery can be drained.

 

With all of the following, whether or not you are using the camera for video makes a big difference.

Digital Cameras

Primary memory

(RAM)

Built-in secondary storage

(HD)

External Disk Storage Processor:
- # / cores,    - speed
- multitasking or not
Cache

RAM: ____

ROM for the system.

Internal:

4 to 256 GB SD card

SD: 100 MB - 2 TB.
XD Picture Code.
Flash Memory.
Smart media.
USB

Image processor -

Network processor (for WiFi) -

 
Limits & Problems Resulting from Reaching those Limits Example: Canon 60D (still pics and video)      

(For this, think of being on a mountain trip with your camera...)

RAM fills up,

After full RAM of a certain # of pics, then they need to go to the secondary storage, and then to work with them further, they would have to be loaded which takes time.

Fills up.

Can't take so many pics or at such high resolution.

And in particular you are limited by the number of minutes of video which can be taken before having to be downloaded to an external drive.

Fills up.

If it fills up, you can always have a second or third hard drive, but that becomes a pain management-wise.

Can't handle certain tasks, or can do them quickly.

Limits you particularly when taking a sequence of high resolution shots in a row. And can limit the kinds of filters that are applied real time as shots taken.

And quality in general will not be as good with a lesser processor.

Hmmmm....

Since if cache exists it would be within the CPU, the same as all CPU limitations and problems

Digital Cameras cont. 

Network Connectivity / Bandwidth

Graphics Processor

& Screen Resolution

Sound processor & Speaker

Relationship to the Cloud Power Consumption/Issues
WiFi & 3G

TFT-LCD display
resolution 10320 x 7752.

Picture resolution:
up to 16 MegaPixels

Has a speaker for the audio part of digital video which the camera can take. Some high level models are set up for cloud storage. Run on a battery alone.
Limits & Problems Resulting from Reaching those Limits       Poor batteries which lose their charge quickly can be a big problem.

Does cloud integration exist?

The limit is the quality which can be uploaded due to the low bandwidth.

The bigger the viewer the better. You pay for what you get.

The limit is the quality of the sound card for recording and playback.

Low sound bit rate and depth will limit quality.

If video, need to be able to review it.

If has access to cloud storage??

Battery runs out, particularly when doing processing intensive work.

Totally limits the portability of the camera. Can drag along extra batteries, but that's a pain, and they can be big and heavy (?).

 

Games Console - XBox

Primary memory

(RAM)

Built-in secondary storage (HD)

External Disk Storage Processor:
- # / cores,    - speed
- multitasking or not
Cache

8 GB DDR3 RAM with a memory bandwidth of 68.3 GB/s

32 MB of "embedded static" RA

500 GB HD, of which, 362 GB of is available for the storage of games   2 x two quad-core, 1.75 GHz each N/A
Limits & Problems Resulting from Reaching those Limits        

If the RAM fills up the game (or other function) can become very slow, because the console has to use the hard-disk.

The hard-drive can fill up, which can prevent any further data from being added. The whole console can become slower, when the RAM is filled and needs to use the hard-disk. No external disk storage. This prevents the user from being able to back-up their data from the console. Data can only be opened/imported from external disks. If the processor gets overloaded by the tasks required by a game, the console will not be able to handle it and start to freeze or become very slow. If a game would require too many repetitive for the game consoles& ; cache, then it could reach its limit, slowing down the whole console.

Games Console - XBox cont.

Network Connectivity / Bandwidth

Graphics Processor

& Screen Resolution

Sound processor & Speaker

Relationship to the Cloud Power Consumption/Issues
Gigabits Ethernet, 802.11n wireless, and WiFi Direct (AMD-based) 12 compute units, which have a total of 768 cores, running at 853 MHz 44.1 KHz  (CD quality sample rate.)

MMORGP games where "masses" of people play at the same time, as with World of Warcraft.

10,000 people at the same time can be playing on the same world (i.e. same "cloud" server).

Plugged into the wall for electricity.
Limits & Problems Resulting from Reaching those Limits       Can't play during a power outage. Have to find other things to do...
Slow network connectivity. This would cause the user to not be able to transfer data from the Internet, which is important when playing on-line, which would decrease the functioning of the console significantly. The graphics processor cannot keep up with certain display tasks. This causes the screen to malfunction or freeze or stutter due to the lower frame rates, which would make game-play impossible. A game console has no sound processor, and only relies on an output with a sound output, without this, there is no sound. Related to Network Connectivity The limit is that if the power is cut, there is no other supply of power, making the console only accessible with a power source, with the compatible power plug.

 

Note that you can use gsmarena.com for the latest phone specifications.

Finally one note related to the AIM Teaching Note (AIM 9 Develop an appreciation of the issues linked to resource availability with continued developments in computer systems.)

With the move toward "The Cloud" (which is, in fact a push that way by the IT companies who want both to control and have access to as much of your personal data as they can, and want to sell you increasing amounts of cloud storage) computer/laptop companies are producing machines which have very little capacity in their secondary storage. In 2015, opting to buy the default Mac with Retina display comes with a mere 128 GB of storage - this is half or a even a quarter of what was supplied to laptops a couple of year previous. This is to force consumers to use cloud storage, but results in full hard drives very quickly. So the "resource availability" of local storage on devices is a major issue.