osx - How to reformat a USB drive with "no file system"?
2014-07
Asu
I have a flash drive I got as some sort of promotion and just for the heck of it I tried to erase it and use it for my purposes. However there is nothing I could do to reformer, erase, zero out, etc this drive. Diskutil info says:
Device Identifier: disk2
Device Node: /dev/disk2
Part of Whole: disk2
Device / Media Name: SMI USB DISK Media
Volume Name: Not applicable (no file system)
Mounted: Not applicable (no file system)
File System: None
Content (IOContent): FDisk_partition_scheme
OS Can Be Installed: No
Media Type: Generic
Protocol: USB
SMART Status: Not Supported
Total Size: 1.0 GB (1018167296 Bytes) (exactly 1988608 512-Byte-Units)
Volume Free Space: Not applicable (no file system)
Device Block Size: 512 Bytes
Read-Only Media: Yes
Read-Only Volume: Not applicable (no file system)
Ejectable: Yes
Whole: Yes
Internal: No
OS 9 Drivers: No
Low Level Format: Not supported
I am doing this on a Mac with OSX 10.9 and it shows up like a perfectly normal file system, folders, hidden files etc.
Is there anything I can do with this drive except throwing it away? Thanks.
Ignacio Vazquez-Abrams
Read-Only Media: Yes
OS says no.
John Doe
I see two possible solutions:
in terminal,
cat /dev/zero > /dev/sd...wheresd...is pendrive's DRIVE designation (not partition path like e.g./dev/sd1). You'd just clobber partition table and everything on it with zeros. That's how it works on Linux though, I have no idea what's the equivalent on OS X.On Windows, I'd use Bootice utility which I dimly remember has the option of formatting it in HDD manner or removing or recreating partition table, etc.
slhck
Some USB drives have a physical write protection switch. If it's in "Read Only" mode, the OS wouldn't be able to write.
Possible solution to your problem is to check if the USB drive has such a switch, and if it does - change it to "Write/Read" mode.
Wilco
Does anyone know of any software that can emulate a USB flash drive through an available USB port in OS X? Perhaps some way to map a directory to a USB port that could then be connected to another device that supports reading USB storage devices?
I'd love to connect my laptop to my car's USB port and access files as if it were a USB drive. I know about the target disk mode with firewire (not sure if this is also supported over USB), but I was hoping for something that doesn't require booting outside of the OS (I want to retain use of the machine).
I'm thinking there may be hardware limitations that prevent software from doing this by itself.
Any ideas?
Spiff
Unfortunately, USB makes a firm distinction between the Host and the Device. If the USB receptacle on your car has the standard USB A (Host) connector like a PC would have, it means the car's computer wants to be the Host, just like your computer wants to be the Host, so they would most likely conflict with each other and not be able to talk to each other.
Some people have made "USB file transfer cables" for connecting two Hosts together. These cables have an embedded chip that does the work of making the two Hosts appear as devices to each other. I believe these products assume both Hosts are full-fledged PCs, not embedded systems that happen to have a Host connector. I don't have experience with these cables, so I'm not sure whether a software install would be required on one or both ends. It might be worth looking into.
The USB Implementers Forum (the body behind the USB spec) eventually realized the limitations of the Host vs. Device distinction, and created the USB On-The-Go (OTG) specification as a way for USB-capable things to switch between the Host and Device roles on the fly as needed, depending on what they're talking to. However, I think you'd probably need both ends to support USB OTG.