Video card.....


13 posts
by rew » Wed Jun 20, 2012 9:27 am
Hi all,

If I buy a raspberry pi video card, do you think it will have VGA out? I have a few spare VGA monitors lying around that'd be nice to use..... The description doesn't say anything about VGA....

http://uk.rs-online.com/web/generalDisp ... aspberrypi

And check out the video card for raspberry pi in the accessories at the bottom of the screen.


:mrgreen:
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by piglet » Wed Jun 20, 2012 9:34 am
No, there is no VGA out. You can use either a ~£2 passive HDMI to DVI-D cable for DVI-D monitors, or an active cable for HDMI to VGA.

You cannot use a passive DVI to VGA converter as there is no analog signal in the HDMI out.

There are several threads on this - have a search.
Last edited by piglet on Wed Jun 20, 2012 9:35 am, edited 1 time in total.
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by RaTTuS » Wed Jun 20, 2012 9:35 am
the RPi is not a video card it is a computer with HDMI out
and no you cannot use a VGA monitor without extra equiptment - see powered HDMI to VGA adaptper - not simple plug
see teh FAQ for more info
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by nidO » Wed Jun 20, 2012 9:35 am
I think you're mis-reading the accessories you're seeing. What you're looking at are SD cards which are labelled as "SD Video Card", ie an SD card advertised as being used for storage for videos from cameras/camcorders, these essentially function as a hard disk for your pi, not a video card as in a device which renders a graphics output.

Edit: or I got trolled.
Last edited by nidO on Wed Jun 20, 2012 9:36 am, edited 1 time in total.
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by jamesh » Wed Jun 20, 2012 9:35 am
Are you being sarky?

Think RS need to be told they have some dodgy descriptive text on their site!!
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by PaulCheffus » Wed Jun 20, 2012 9:37 am
jamesh wrote:Are you being sarky?

Think RS need to be told they have some dodgy descriptive text on their site!!


Hi

I took it as sarcasm due to the smiley.

Cheers

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by RaTTuS » Wed Jun 20, 2012 9:42 am
IC see you mean
http://uk.rs-online.com/web/p/flash-memory/7276403/
as that was not being shown when I looked ....
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by Joe Schmoe » Wed Jun 20, 2012 10:38 am
But it is true that the RS page advertises "4Gb SD video card" - and I've never heard that terminology before. It does seem awfully dodgy to call an SD card a "video card", just because you could store videos (or anything else) on it...

Incidentally, if this was a "troll" thread, then well done! sir. Kudos to the OP.
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by domesday » Wed Jun 20, 2012 11:05 am
RS are not exactly known for their superior product knowledge ;)
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by rew » Fri Jun 22, 2012 7:50 pm
:-) I like to make jokes that take a while to sink in.

This was a successful one. :-)

- RS doesn't really understand what they are selling.
- RS needs to be told that their description of the SD card is misleading.

On the other hand, apparently some SD cards are specifically engineered to be good at storing videos. Just like ten years ago you had video harddisks. The idea is that if you gear your equipment towards storing and retrieving videos, it's much more important to achieve a good average bandwidth than to be able to cough up ALL the data. A video harddisk would rather report a bad block after 1 second than retry for a minute with a chance for success somewhere during that time....

In the case of SD cards, this could mean that they don't pause to do a "defrag" but would defrag on-the-fly, i.e. a little bit between every command, and not the whole defrag in one go.

Someone asked why a 3 second timeout for an SD card was necessary. Well, some cards do that, sometimes. They suddenly realize they need the defrag and then go do it before they answer the next request. Lots longer than you'd expect. Anyway, the video-sd-cards are supposed not to do that.
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by Burngate » Sat Jun 23, 2012 11:18 am
Had a problem at work - video-disk recorders sometimes wouldn't play ball. Turned out the (SCSI) drives were configured for systems such as banks, who didn't care how long the drive took to get the data, just as long as they got it eventually. For video, you want the data now, otherwise forget it - we've moved on.
Apparently there was a hardware flag you could set on some (but not all) SCSI drives for software-recovery of the data.
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by rew » Sat Jun 30, 2012 10:54 am
Actually MOST SCSI harddisks have that option.

And yes, the default is the "get the data, I don't care how long it takes".

I also work at http://www.harddisk-recovery.nl, and SCSI disks with bad blocks are a snap to recover. With IDE or SATA drives we can't get at these parameters. So when a drive has say 0.01% bad blocks, it really pays to stay away from those bad blocks. Each bad block takes half a minute, you can do the math how long it would take to scan a 500Gb disk once to find the 1/10000 bad blocks.

Now with a SCSI drive, it's easy to tell it: You have a 20ms deadline for delivering my data. If you don't have it by then, give up and allow me to specify what other data to get. The 20ms allows for a retry on the next rotation of the platter, but nothing more. You'll have something like 99.98 % of the blocks in the three hours that you already expected that it would take to image the whole drive. Now we get to retry those 2/10000 blocks with a slightly longer "deadline".

But by that time we usually have enough data to KNOW where the interesting bits are. We can also let it specifically try those bits that are in the files that the client actually needs....
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by Ilikepi » Sat Jul 07, 2012 2:49 pm
rew wrote:Hi all,

I have a few spare VGA monitors lying around that'd be nice to use

:mrgreen:

Could I buy a monitor from you? No cash for a new one right now, so if they're worth more than about £50 then I can't afford it.
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