What exactly are you worrying about - and will RAID protect it all? I think maybe not. Some things RAID will *not* help with:
1)Theft of the machine 2)PSU failure in the machine (this happened to me, and fried every single drive with 240V on the 12V rail!) 3)Lightening (could kill every machine in your house) 4)Fire. 5)HDD failure. 6)Catastrophic OS failure (filesystem corruption, conveniently mirrored), or a worm/trojan/virus.
RAID does give you convenience, slightly better performance, and ease of repairing the most common fault. But it sounds to me as though reliability and backup safety matter more to you than a few hours of downtime. My suggestion:
1)Don't use RAID; use separate machines. [Maybe mini-itx ?] 2)If possible, put one of them somewhere else. 3)Rsync + SSH - see here: http://www.mikerubel.org/computers/rsync_snapshots / 4)Offline Backup (CD ROM, or external HDD) in safe place (eg bank) for really important documents. 5)If you have remote backups, make sure you encrypt them. If you dispose of old CD-Rs, destroy them first. Likewise old HDDs.
P.S. I've had a lot of HDD failures over the last 5 years (Mainly IBM Deskstars). 2 years ago, I switched to the Seagate Barracudas en masse. So far, so good:-) At least Seagate give a 5-year warranty, which suggests you might reasonably get a 5 year MTBF.
Likewise when British Airways decided to re-brand: they irritated their customers, lost international recognition (really, people *liked* them to be British), and caused maintenance chaos too (by adding such somplex colour-schemes that their engineers couldn't check the tail for cracks). This cost millions, at the same time that they were laying people off - and thus caused a strike, and further chaos. The killer for them was when Margaret Thatcher gave a speech, and on the podium was a model of the newly painted aircraft. She tied her handkerchief around the tail to cover the new logo! In the end, BA also reversed the damage.
It occurs to me that, except for writing letters, "Office" applications are not as useful as people think. In particular:
- Word processors are an uncomfortable hybrid of document formatting (better done in latex), content production (better done in html; layout independent) and desktop publishing. I've lost count of the number of times I get Word attachments which ought to be part of the plaintext in the email!
- Spreadsheets are used mainly by people who don't understand databases! [Corollary: Access is a toy used by people who can't use Excel]
- Presentation software is almost invariably abused to hide substance with style.
Given that all these technological measures only break Windows because of Autorun, why doesn't MS issue a patch to disable it. All that would be required is a simple popup when you insert a CD: "This disc appears to be an audio disc. Do you want to play it as normal, or would you like to install the program that is on the disc".
Sorry - this is plain wrong. I am also a physicist, at Cambridge University. Even though we have access to the physical journals (and to electronic ones too), I have found the system immensely frustrating. The Web of Science is a dreadful tool to use - even if you have the privilege of access to it. It's nothing like as good as Google, and furthermore, hunting down the papers once you have found the reference is often time consuming[*]. And even Cambridge cannot subscribe to everything. Furthermore, if one is a teacher, an amateur scientist, a researcher in the 3rd world, these journals are beyond ones's reach.
What is really immoral, however, is that the journals in which one must publish (in order to be peer reviewed, in order to be read, and in order to keep the grants panels happy) usually insist that by publishing, you are assigning your copyright to them, and you may not publish your own work on the web. The journals are using their monopoly to take publicly funded research out of the public domain, and are very damaging to the progress of science.
[*] for non-academics, I should explain that the WoS is a search tool for abstracts of papers. Once you find a result, if you want to read the whole article, all you get is a reference eg "Journal X, issue Y, pages ppp-qqq". Then, you have to hunt down that journal on-line, and hope that your institution has a subscription. At best, a literature search that should take a few hours will take a day. At worst, many materials are inaccessible.
My research was significantly impeded by this system. But, for what it is worth, my thesis is on the web.
Hmm. it is slow, but not very slow. Then again, I'm using a 3GHz P4 with 2GB RAM, and so I'm not altogether unhappy with the performance. The VM (without KQEMU) feels like it's about 400 Mhz, with 256 MB RAM, so although I wouldn't call it speedy, it is, however, quite usable. Win98 boots in 20 seconds, and takes another 15 to start firefox. KQEMU is nice - I just haven't bothered to recompile it yet.
Re:The $sys$ prefixing thing was apparently wrong
on
Sony Rootkit Phones Home
·
· Score: 2, Informative
An alternative to VMWARE is the excellent, and free QEMU.
There is a huge wrong assumption here. We shouldn't make the police's job easy. Catching criminals ought to be difficult, and surveillance ought to be expensive. This is one of the ways to ensure that surveillance does not become too pervasive, and that we remain innocent until proven guilty. Furthermore, if released "without charge", one ought to be entitled to compensation.
I happen to have the good fortune to work on The Magdalena Ridge Observatory Interferometer. We're beginning construction very soon, and it is the successor to the
COAST telescope in Cambridge.
The advantage of interferometers is that we can have the effective aperture of 400m (so obtaining high angular resolution) without the problem of building and maintaining a distortion-free enormous mirror. Of course, we don't get the sensitivity, but we do get the resolution.
Incidentally, COAST (Cambridge Optical Aperture Synthesis Telsecope), which was built in the late '80s has a better angular resolution than Hubble (although we do have a lot of atmosphere in the way!), and has managed to sucessfully image detail on the surface of stars.
Really, it would be better if they called them "shortscreens". Eg a 15" 'widescreen' LCD is SMALLER than a 15" regular screen. Also, for those of use who really don't care about DVDs on laptops, short screens are a curse. Most documents and websites are Portrait mode. Likewise, photo editing - unless it's all landscapes. And most U.I.s have everything on the top and bottom (title-bar, menu bar, taskbar), so more *vertical* space is needed!
I wonder: if you are aiming at something that is suddenly getting extremely hot, won't that point on the boat also be incredibly bright? i.e. isn't there a serious risk to the person doing the aiming?
1)Is the value of k known (in advance) by the prisoners?
2)"The only rule the king has to obey is that eventually he has to call every prisoner in an arbitrary number of times." Does this mean that at some point, all prisoners have been called in the same number, n, of times? [Where n is unknown, but is at some point equal for all prisoners]
The easy way to build this is out of a PIC microcontroller. They cost about $2, and you can easily reprogram them in circuit. PICs are very easy to learn, and work well for this sort of thing.
Also, you have to use RF for the transmission. You can buy some RF transmitter modules for about $10 which are very easy to use.
The problem is how to avoid interference. Why not interrogate each device in turn. I.e.
Everyone press a button; is stored in devices.
Server To Device1: What is your code?
Device1: my code is XXX-YYY (XXX = serial no; YYY= answer)
Or wait 1 second for timeout
Server to Device2:....
Or, if everyone has a wifi laptop, then you can make what you want very easily.
I recommend the adblock extension. Block all the ads - and everything becomes much faster. Personally, I have lots of bandwith, so as a courtesy to site owners, I usually load the ads. But if the ad server's performance is so poor that it takes 15 seconds to load the page - well, I'm going to block them.
1)Skype isn't open-source. You can't read the source code, therefore you can't necessarily trust it. I'm not naturally inclined to give the makers of kazaa the benefit of the doubt.
2)Skype is gratuitously incompatible with the rest of the world, and uses a closed protocol. This is unforgivable.
3)Skype is P2P - which means that in some cases, such as Cambridge University, it cannot be used, because a user of the university network may not grant network bandwidth to non-members.
If you want a good Linux SIP phone, try Linphone + FreeWorld Dialup.
Re:The annoyances of Mozilla products (Windows)
on
Firefox 1.05 Released
·
· Score: 1
That's useful to know. I'm using the official build. (from Mandrake)
Re:The annoyances of Mozilla products (Windows)
on
Firefox 1.05 Released
·
· Score: 1
On Linux, multiple profile support is a bug, plain and simple. I'd love to disable it globally. The problem occurs when you try to open a second instance of the program, (because another one is running, or maybe has a lock still open due to a crash/os-crash, or power failure), and are invited to create another profile. This causes real trouble for non technical users.
Most cases, you just want something really simple, easy to implement, and understand. So, why not use SCP. It's secure, easy to set up (all you need on the server is Linux + SSH), and easy to access.
In konqueror, type scp:// or fish://. In Windows, use the free WinSCP program In MacOsX - you have ssh/scp.
Other advantage: if you give them a linux box to access, then it's easy to control private vs group vs public.
Except that most brailled devices only give you ONE line of text at 80 columns. Some of them are only 20 cols in order to reduce the cost. So the terseness of bash is actually a blessing.
Besides which, learning a few dozen comands (cd,cat,ls,mv etc) is hardly going to take very long.
Slashdot Mirror
What exactly are you worrying about - and will RAID protect it all? I think maybe not. Some things RAID will *not* help with:
s /
:-) At least Seagate give a 5-year warranty, which suggests you might reasonably get a 5 year MTBF.
1)Theft of the machine
2)PSU failure in the machine (this happened to me, and fried every single drive with 240V on the 12V rail!)
3)Lightening (could kill every machine in your house)
4)Fire.
5)HDD failure.
6)Catastrophic OS failure (filesystem corruption, conveniently mirrored), or a worm/trojan/virus.
RAID does give you convenience, slightly better performance, and ease of repairing the most common fault. But it sounds to me as though reliability and backup safety matter more to you than a few hours of downtime. My suggestion:
1)Don't use RAID; use separate machines. [Maybe mini-itx ?]
2)If possible, put one of them somewhere else.
3)Rsync + SSH - see here: http://www.mikerubel.org/computers/rsync_snapshot
4)Offline Backup (CD ROM, or external HDD) in safe place (eg bank) for really important documents.
5)If you have remote backups, make sure you encrypt them. If you dispose of old CD-Rs, destroy them first. Likewise old HDDs.
P.S. I've had a lot of HDD failures over the last 5 years (Mainly IBM Deskstars). 2 years ago, I switched to the Seagate Barracudas en masse. So far, so good
Likewise when British Airways decided to re-brand: they irritated their customers, lost international recognition (really, people *liked* them to be British), and caused maintenance chaos too (by adding such somplex colour-schemes that their engineers couldn't check the tail for cracks). This cost millions, at the same time that they were laying people off - and thus caused a strike, and further chaos. The killer for them was when Margaret Thatcher gave a speech, and on the podium was a model of the newly painted aircraft. She tied her handkerchief around the tail to cover the new logo!
In the end, BA also reversed the damage.
It occurs to me that, except for writing letters, "Office" applications are not as useful as people think. In particular:
- Word processors are an uncomfortable hybrid of document formatting (better done in latex), content production (better done in html; layout independent) and desktop publishing. I've lost count of the number of times I get Word attachments which ought to be part of the plaintext in the email!
- Spreadsheets are used mainly by people who don't understand databases! [Corollary: Access is a toy used by people who can't use Excel]
- Presentation software is almost invariably abused to hide substance with style.
But even admins make mistakes. Autorun is a bug, not a feature.
Given that all these technological measures only break Windows because of Autorun, why doesn't MS issue a patch to disable it.
All that would be required is a simple popup when you insert a CD: "This disc appears to be an audio disc. Do you want to play it as normal, or would you like to install the program that is on the disc".
Sorry - this is plain wrong. I am also a physicist, at Cambridge University. Even though we have access to the physical journals (and to electronic ones too), I have found the system immensely frustrating. The Web of Science is a dreadful tool to use - even if you have the privilege of access to it. It's nothing like as good as Google, and furthermore, hunting down the papers once you have found the reference is often time consuming[*]. And even Cambridge cannot subscribe to everything. Furthermore, if one is a teacher, an amateur scientist, a researcher in the 3rd world, these journals are beyond ones's reach.
What is really immoral, however, is that the journals in which one must publish (in order to be peer reviewed, in order to be read, and in order to keep the grants panels happy) usually insist that by publishing, you are assigning your copyright to them, and you may not publish your own work on the web. The journals are using their monopoly to take publicly funded research out of the public domain, and are very damaging to the progress of science.
[*] for non-academics, I should explain that the WoS is a search tool for abstracts of papers. Once you find a result, if you want to read the whole article, all you get is a reference eg "Journal X, issue Y, pages ppp-qqq". Then, you have to hunt down that journal on-line, and hope that your institution has a subscription. At best, a literature search that should take a few hours will take a day. At worst, many materials are inaccessible.
My research was significantly impeded by this system. But, for what it is worth, my thesis is on the web.
Try mplayerplugin
Hmm. it is slow, but not very slow. Then again, I'm using a 3GHz P4 with 2GB RAM, and so I'm not altogether unhappy with the performance. The VM (without KQEMU) feels like it's about 400 Mhz, with 256 MB RAM, so although I wouldn't call it speedy, it is, however, quite usable. Win98 boots in 20 seconds, and takes another 15 to start firefox.
KQEMU is nice - I just haven't bothered to recompile it yet.
An alternative to VMWARE is the excellent, and free QEMU.
Someone also registered the excellent "wehavethewayin.com" which had a great intro to Linux/BSD. Sadly. it's now gone.
There is a huge wrong assumption here. We shouldn't make the police's job easy. Catching criminals ought to be difficult, and surveillance ought to be expensive. This is one of the ways to ensure that surveillance does not become too pervasive, and that we remain innocent until proven guilty. Furthermore, if released "without charge", one ought to be entitled to compensation.
Fair point. Funding is a nuisance to get. However, we have the money for almost the whole telescope in advance. :-)
I happen to have the good fortune to work on The Magdalena Ridge Observatory Interferometer. We're beginning construction very soon, and it is the successor to the COAST telescope in Cambridge.
The advantage of interferometers is that we can have the effective aperture of 400m (so obtaining high angular resolution) without the problem of building and maintaining a distortion-free enormous mirror. Of course, we don't get the sensitivity, but we do get the resolution.
Incidentally, COAST (Cambridge Optical Aperture Synthesis Telsecope), which was built in the late '80s has a better angular resolution than Hubble (although we do have a lot of atmosphere in the way!), and has managed to sucessfully image detail on the surface of stars.
Really, it would be better if they called them "shortscreens". Eg a 15" 'widescreen' LCD is SMALLER than a 15" regular screen.
Also, for those of use who really don't care about DVDs on laptops, short screens are a curse. Most documents and websites are Portrait mode. Likewise, photo editing - unless it's all landscapes. And most U.I.s have everything on the top and bottom (title-bar, menu bar, taskbar), so more *vertical* space is needed!
I wonder: if you are aiming at something that is suddenly getting extremely hot, won't that point on the boat also be incredibly bright? i.e. isn't there a serious risk to the person doing the aiming?
2 things seem unclear:
1)Is the value of k known (in advance) by the prisoners?
2)"The only rule the king has to obey is that eventually he has to call every prisoner in an arbitrary number of times."
Does this mean that at some point, all prisoners have been called in the same number, n, of times? [Where n is unknown, but is at some point equal for all prisoners]
The easy way to build this is out of a PIC microcontroller. They cost about $2, and you can easily reprogram them in circuit. PICs are very easy to learn, and work well for this sort of thing.
....
Also, you have to use RF for the transmission. You can buy some RF transmitter modules for about $10 which are very easy to use.
The problem is how to avoid interference. Why not interrogate each device in turn. I.e.
Everyone press a button; is stored in devices.
Server To Device1: What is your code?
Device1: my code is XXX-YYY (XXX = serial no; YYY= answer)
Or wait 1 second for timeout
Server to Device2:
Or, if everyone has a wifi laptop, then you can make what you want very easily.
I suspect that it is easy to go from MySQL -> Postgres and rather hard to go the other way.
It depends how complex your project is.
In PHP, it would basically be a matter of
0)Migrate the database itself. Hopefully, just dump to SQL, then re-import. [Then fix any complicated stuff!]
1)replace all function calls of mysql_foo() by
pg_foo().
2)re-write any really complex SQL that fails.
3)Test it.
There is a gui (pg_access), but the psql command-line tool is so good that you are unlikely to need it.
I recommend the adblock extension. Block all the ads - and everything becomes much faster. Personally, I have lots of bandwith, so as a courtesy to site owners, I usually load the ads. But if the ad server's performance is so poor that it takes 15 seconds to load the page - well, I'm going to block them.
Thank you - I stand corrected.
You missed out some key disadvantages:
1)Skype isn't open-source. You can't read the source code, therefore you can't necessarily trust it. I'm not naturally inclined to give the makers of kazaa the benefit of the doubt.
2)Skype is gratuitously incompatible with the rest of the world, and uses a closed protocol. This is unforgivable.
3)Skype is P2P - which means that in some cases, such as Cambridge University, it cannot be used, because a user of the university network may not grant network bandwidth to non-members.
If you want a good Linux SIP phone, try Linphone + FreeWorld Dialup.
That's useful to know. I'm using the official build. (from Mandrake)
On Linux, multiple profile support is a bug, plain and simple. I'd love to disable it globally. The problem occurs when you try to open a second instance of the program, (because another one is running, or maybe has a lock still open due to a crash/os-crash, or power failure), and are invited to create another profile. This causes real trouble for non technical users.
Most cases, you just want something really simple, easy to implement, and understand. So, why not use SCP. It's secure, easy to set up (all you need on the server is Linux + SSH), and easy to access.
In konqueror, type scp:// or fish://.
In Windows, use the free WinSCP program
In MacOsX - you have ssh/scp.
Other advantage: if you give them a linux box to access, then it's easy to control private vs group vs public.
Except that most brailled devices only give you ONE line of text at 80 columns. Some of them are only 20 cols in order to reduce the cost. So the terseness of bash is actually a blessing.
Besides which, learning a few dozen comands (cd,cat,ls,mv etc) is hardly going to take very long.