(old)Puppy Linux Discussion Forum

I have tried SD cards from various cameras by plugging them into 7 in 1 readers and directly in an SD only type reader. None of them are picked up by Pmount or mutt

Anyone know whats happening here?

Which version of Puppy? How old is the computer hardware?

Puppy 5.31
Compyters Dell Optiplex 740 & 745 Fairly modern 2.7 Mhz

Hmm my general experience of puppy is that it will not detect a card inserted into a reader... ie it has to be inserted into the reader and then that is inserted into the usb port.
This may or may not be related to your issue

regards

Mike

I don't know why you would use a PM for this but I have tried it both ways to no avail

I tried it in a Windows 7 Laptop I have and it came up saying it could not format it . When I put the card in the laptops slot it worked fine ?

Card readers do not send any sort of hardware signal when a card is plugged in. The system only sees a single device -unless the card is plugged in when the reader gets connected.

amigo wrote:Card readers do not send any sort of hardware signal when a card is plugged in. The system only sees a single device -unless the card is plugged in when the reader gets connected.

Ehh?
The card reader usually comes up with something like 5 addresses on windows in the mycomputer directory
Clicking on one asks you to insert a card
When you do you get the card directory listing

Are you saying this does not happen in Linux or do you mean Puppy?

I would expect these readers to return the normal USB data when plugged in.
Such as power requirements , manufacturer id and numbers,interface descriptors,endpoints etc etc - do you know what I mean ?

I happened to have a card reader nearby just and tried it for the first time on Puppy 525, no problems : it reads the SD card whether it is in the reader when the reader is plugged into the USB port, or if you plug the empty card reader into the USB port then plug the SD card into the card reader.

[ BTW If you are trying to get photos off of corrupted memory try photorec ... http://www.theunixtips.com/recover-photos-corrupted-memory-card-photorec ]

Yes thanks for the Photorec
Had Plenty for windows but none for Linux

I.m starting to think its time to change the card reader

It's been my experience that some old card readers won't read the new generation of SD cards.

tytower, sorry I had not seen your question. You mention a behaviour under windows which is not duplicated under linux. pmount and other 'mount helpers' may handle hotplugged cards, but that is not 'Linux' doing that. Since the hardware *itself* does not send any signal, the OS cannot do anything with a hotplugged card -unless some software is running which periodically *polls* for devices or new partitions. The closest the *kernel* comes to this, is that in newer kernels, polling *can be* done in the kernel itslef -although this does not mean that the kernel does anything with the device. The most the kernel can do is send a signal to hotplug which can then be directed to run some program which will mount the new partition.

It's the same regarding a CD drive -when closing or opening the drive tray, no hardware signal is sent. Hence, the only way for the OS to know when and how the status of the drive has changed is by polling the device.

Polling works fine, with the right logic. It's just that polling is an expensive process which most of the time is just waiting, but still consuming resources.

Yes OK Thanks .
I don't think it gets me any further out of the mystery.
The micro sd cards seem to read fine in the old gear I have but not its larger brother.

Later issues of card readers seem to read it fine but not older models