Fastest way to create ramdisk in Ubuntu/Linux

Fastest way to create ramdisk in Ubuntu/Linux: "

I hope many of you will agree that sometimes it’s really good idea to have some small amount of RAM mounted as a filesystem. It may be necessary when running some bash or perl script that handles, say, thousands of small files so it’s much more effective not to waste computer resources on reading/writing data on hard disk but keep those files directly in memory. This idea is known as Virtual RAM Drive or ramdisk and can be setup in Ubuntu or almost any other Linux distribution using the following commands under root (to become root in Ubuntu use 'sudo -s“):

# mkdir /tmp/ramdisk; chmod 777 /tmp/ramdisk

# mount -t tmpfs -o size=256M tmpfs /tmp/ramdisk/

where 256M is amount of RAM you wish to allocate for ramdisk. It’s clear that this value should be less than amount of free memory (use “free -m“). BTW, if you specify too many MBs for ramdisk Linux will try to allocate it from RAM and then from swap so resulting performance would be very poor.

"

Waiting for a mobile device to die....

The Problem:

I strikes me as my Samsung PMP slowly dies next to me that waiting for a mobile device to die these days is very much like baking.  Like how opening the door on a delicate suflay do check if it's done would ruin it, if I keep waking the Samsung up to check how much is left I simply drain it more.  The screen is the biggest battery drain of all.  So a couple of things wind me up about this situation.  One is that the only connector (apart from the headphone jack) is this proprietary Samsung crap - so I can't plug it into one of my abundant USB ports I have lying around.  For crying out loud, my alarm clock has 2 in it!  The other thing that does my head in, is that these devices that are running out of battery seem to go out of their way to drain themselves telling you.  Thus hastening their demise considerably.

The solution:

Okay, there are two simple answers to end this nonsense.

1. Use standard USB ports everywhere.  If this isn't suitable for the device (due to form factor) then introduce a third form factor to USB (to compliment the two USB already has) that has a slimmer profile.  

Of course a better solution might be to actually adapt the other existing port these devises have.

2.  Many of the devices I'm talking about all have a standard 3.5mm mini-jack... or headphone socket if you will.  So why can't that supply power, just like USB does?   Think of the benefits!  Devices could charge each other!  I wonder what the complications of sending a charge over the same wire that's carrying signal.  If that weren't possible, then it would mean a redesign of the 3.5mm plug/socket spec, which probably makes it infeasible.

Oh well.  My device is still running, and hopefully the suflay is not ruined.  Oh yea, and on these stupid devices that constantly alert about dying... make them smart. Put them in low power mode (at the least dim the screen). Have a semi-awake mode where the first stage wakeup is just a dim power read out.  To wake fully, just press on again.

Bet's on any of this actually happening....

Temporary tables, union and union all

Temporary tables, union and union all: "Both UNION and UNION ALL use a temporary table to buffer results from all branches of the query. The temporary table buffers all rows before any are returned to the client. For UNION, a unique index is created on the table. For UNION ALL, a unique index is not created. The HEAP (MEMORY) engine is used as long as there are no LOB columns.

The HEAP engine uses fixed length rows. For variable length columns each row allocates the max size per column so a lot of memory can be wasted. When the temp table gets too big, it is converted to a MyISAM table. The switch is done when the size of the table is min(max_heap_table_size, tmp_table_size) (I think that equation is right, wouldn't it be nice if it were simpler?).

In some cases UNION ALL can be used to reduce network round trips when there are multiple SELECT statements that return similar columns: select * from foo UNION ALL select * from bar. While this reduces network latency, it can increase the load on the server from writing the temporary table.

A feature request might be open to not use a temporary table for UNION ALL. Search for more details on this topic.

What happened to the change to not allocate the max length for variable length columns in the HEAP engine? When will it appear in an official release? There is a feature request for it.

And now, a quiz from Domas. What is done for the following?

(select * from foo UNION ALL select * from bar) limit 10

PlanetMySQL Voting:
Vote UP /
Vote DOWN"

Windows 7 Automatic Update Shutdown HELL

So I came in this morning and Windows 7 had rebooted my PC.  I had 7.5GB of applications running across two operating systems (Ubuntu running in a Virtualbox - connected to lots of servers for work).  This made me very mad.  I had updated Windows Update to only download the updates, and let me choose when to install them.  I had installed them - and suffered the annoying "Reboot now for Important updates to be installed"  and I kept postponing it for 3 hours.  The last thing I expected was to come in and find that windows got fed-up asking me and decided to reboot anyway.

Well, I found a way to stop it - and thought I'd share it here as Google seems to return mainly crap about the BETA version rebooting when it's about to expire.  Convenient me thinks - this will mask any REAL issues with Windows 7 rebooting.

Anyway - here's the link:  http://www.howtogeek.com/howto/windows-vista/prevent-windows-update-from-forcibly-rebooting-your-computer/

Google Profiles Turn Into OpenIDs

Google Profiles Turn Into OpenIDs: "

As part of its push to go more social, Google has been attempting to unify its various account profiles into one Google Profile. And now it’s more useful. Google’s Brad Fitzpatrick has just tweeted out that Google Profiles can now be used as OpenIDs.

What this means is that you can sign into any site that accepts OpenID simply by using your Google Profile domain. Luckily, a few months ago Google started allowing these profiles to have vanity URLs, like /mgsiegler, instead of the previous /32090329039402903. Chris Messina, a huge proponent of the open web movement, has just sent out a picture of what signing in with OpenID via your Google Profile looks like (below).

Despite its good intentions, OpenID has yet to take off in mainstream usage. The problem, it seems, is largely about presentation. Most people have no idea which of their various accounts can be used as OpenIDs, or really even what OpenID is. Google backing it a bit more with these profiles obviously helps, but will it take OpenID mainstream? Probably not.

More interesting may be the second part of Fitzpatrick’s tweet. “Also, gmail webfinger declares that now too.” It’s not entirely clear what he means by that, but it would seem to suggest that we’re getting closer to being able to use our Gmail addresses as a web ID. WebFinger is a protocol being worked on by Fitzpatrick to allow you to attach information to your email address (in this case, you Gmail address), so it can be used as a solid means of identification.

Update: Kevin Marks (former Googler, now with BT) has pointed me to webfinger.org an example site built by Blaine Cook (formerly of Twitter). The site allows you to easily set up your Gmail account with Webfinger right now. As you can see in the example below from Cook’s account, many of the social networks Cook is a part of are pinned to his email address.

CrunchBase Information

Google

Information provided by CrunchBase

Crunch Network: CrunchGear drool over the sexiest new gadgets and hardware.

"

Google Profiles Turn Into OpenIDs

Google Profiles Turn Into OpenIDs: "

As part of its push to go more social, Google has been attempting to unify its various account profiles into one Google Profile. And now it’s more useful. Google’s Brad Fitzpatrick has just tweeted out that Google Profiles can now be used as OpenIDs.

What this means is that you can sign into any site that accepts OpenID simply by using your Google Profile domain. Luckily, a few months ago Google started allowing these profiles to have vanity URLs, like /mgsiegler, instead of the previous /32090329039402903. Chris Messina, a huge proponent of the open web movement, has just sent out a picture of what signing in with OpenID via your Google Profile looks like (below).

Despite its good intentions, OpenID has yet to take off in mainstream usage. The problem, it seems, is largely about presentation. Most people have no idea which of their various accounts can be used as OpenIDs, or really even what OpenID is. Google backing it a bit more with these profiles obviously helps, but will it take OpenID mainstream? Probably not.

More interesting may be the second part of Fitzpatrick’s tweet. “Also, gmail webfinger declares that now too.” It’s not entirely clear what he means by that, but it would seem to suggest that we’re getting closer to being able to use our Gmail addresses as a web ID. WebFinger is a protocol being worked on by Fitzpatrick to allow you to attach information to your email address (in this case, you Gmail address), so it can be used as a solid means of identification.

Update: Kevin Marks (former Googler, now with BT) has pointed me to webfinger.org an example site built by Blaine Cook (formerly of Twitter). The site allows you to easily set up your Gmail account with Webfinger right now. As you can see in the example below from Cook’s account, many of the social networks Cook is a part of are pinned to his email address.

CrunchBase Information

Google

Information provided by CrunchBase

Crunch Network: CrunchGear drool over the sexiest new gadgets and hardware.

"

Google Profiles Turn Into OpenIDs

Google Profiles Turn Into OpenIDs: "

As part of its push to go more social, Google has been attempting to unify its various account profiles into one Google Profile. And now it’s more useful. Google’s Brad Fitzpatrick has just tweeted out that Google Profiles can now be used as OpenIDs.

What this means is that you can sign into any site that accepts OpenID simply by using your Google Profile domain. Luckily, a few months ago Google started allowing these profiles to have vanity URLs, like /mgsiegler, instead of the previous /32090329039402903. Chris Messina, a huge proponent of the open web movement, has just sent out a picture of what signing in with OpenID via your Google Profile looks like (below).

Despite its good intentions, OpenID has yet to take off in mainstream usage. The problem, it seems, is largely about presentation. Most people have no idea which of their various accounts can be used as OpenIDs, or really even what OpenID is. Google backing it a bit more with these profiles obviously helps, but will it take OpenID mainstream? Probably not.

More interesting may be the second part of Fitzpatrick’s tweet. “Also, gmail webfinger declares that now too.” It’s not entirely clear what he means by that, but it would seem to suggest that we’re getting closer to being able to use our Gmail addresses as a web ID. WebFinger is a protocol being worked on by Fitzpatrick to allow you to attach information to your email address (in this case, you Gmail address), so it can be used as a solid means of identification.

Update: Kevin Marks (former Googler, now with BT) has pointed me to webfinger.org an example site built by Blaine Cook (formerly of Twitter). The site allows you to easily set up your Gmail account with Webfinger right now. As you can see in the example below from Cook’s account, many of the social networks Cook is a part of are pinned to his email address.

CrunchBase Information

Google

Information provided by CrunchBase

Crunch Network: CrunchGear drool over the sexiest new gadgets and hardware.

"