Virtual CD-ROM switching utility: Difference between revisions

Revision as of 10:46, 8 August 2024

Revision as of 11:07, 8 August 2024

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{{Short description|Programs to disable the virtual CD-ROM drive}}

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'''Virtual CD-ROM switching utilities''' are programs to disable the virtual [[CD-ROM]] drive found on some devices like [[mobile broadband modem]].<ref>{{Cite web |url=http://www.pharscape.org/usb_modeswitch.html |title=USB_modeswitch Virtual CD-ROM switching utility |access-date=2010-11-03 |archive-url=https://web.archive.org/web/20100212225215/http://www.pharscape.org/usb_modeswitch.html |archive-date=2010-02-12 |url-status=dead }}</ref>{{failed verification|date=August 2024}}{{Unreliable source|1=|certain=y|date=August 2024}} A virtual CD-ROM switching utility is a mode switching tool for controlling "flip flop" (multiple device) [[Universal Serial Bus|USB]] gear. Several USB devices (especially high-speed wireless [[Wide area network|WAN]] equipment offer a feature where they have their [[Microsoft Windows]] device drivers onboard; when plugged in for the first time they act like a [[USB flash drive]] and start installing the device driver from there. All succeeding insertions of the device switches the mode internally, resulting in the virtual CD-ROM drive or [[USB mass storage device class]] disappearing and being replaced with the actual device itself. The [[Wireless WAN]] (WWAN) gear maker [[Option N.V.|Option]] calls that feature "ZeroCD (TM)". With USB sniffing programs and [[libusb]] it is possible to eavesdrop the communication of the Windows device driver and isolate the [[Command (computing)|command]] or action that does the switching and to reproduce the same event under an unsupported environment like [[Linux distribution|Linux]] or [[BSD]] variants.<ref name="usb_modeswitch">{{Cite web|url=http://www.draisberghof.de/usb_modeswitch/|title=USB_ModeSwitch - Activating Switchable USB Devices on Linux}}</ref>{{failed verification|date=August 2024}}{{Unreliable source|1=|certain=y|date=August 2024}}

The problem with most USB [[3G]] modems is they have two modes. In one mode they are a USB flash drive and in the other mode they are a modem. Typically they only ship with Windows device drivers, sometimes [[Macintosh|Mac]] device drivers as well. In any case, they seemingly seldom, if ever, ship with Linux device drivers. What normally happens with Windows is the device starts up as a USB flash drive, the [[Computer hardware|hardware]] drivers are installed and then they are responsible for "switching" the device in to modem mode so you can use it. This "switch" is done via some codes, specific to the device, which controlling software can pass as a command to switch from disk to modem mode. The virtual CD-ROM switching utility manages the switch of mode from disk to modem, the latter disconnects any mounted disk containing software we do not care about that will not work anyway and, crucially, creates a modem port/serial device (usually {{mono|/dev/ttyUSB0}}) for the networkmanager.<ref name="3g_usb_modems ">{{Cite web|url=http://www.drupaler.co.uk/blog/installing-3g-usb-modems-linux/497|author=greg.harvey|title=Installing 3G USB Modems On Linux|date=28 April 2010|archive-url=https://web.archive.org/web/20120421021905/http://www.drupaler.co.uk/blog/installing-3g-usb-modems-linux/497|archive-date=2012-04-21|access-date=2019-02-10}}</ref>{{failed verification|date=August 2024}}{{Unreliable source|1=|certain=y|date=August 2024}}

The approach of adding Virtual CD-ROM with software drivers on 3G or storage devices has two problems: it presumably raises the cost of the device, and it may ship outdated software or even viruses. Most of the times, up-to-date drivers are anyway built into the operating systems (after all, on systems implementing the USB standard like Linux, any 3G device is a USB serial port, and any storage device is a ... USB storage device). Virtual CD-ROM on U3-compatible devices can be removed by a software tool.<ref>{{cite web|url=http://u3-tool.sourceforge.net/|title=u3_tool - Tool for controlling U3 drives|access-date=2021-01-04|website=[[SourceForge]]}}</ref>{{failed verification|date=August 2024}}{{Unreliable source|1=|certain=y|date=August 2024}} Some 3G devices such as the Huawei support complete disabling of the Virtual CD-ROM.<ref>{{cite web|url=http://www.techytalk.info/disable-virtual-cd-rom-drive-with-built-in-software-on-huawei-and-zte-gsm-modem-devices/|last=Martinović|first=Marko|title=Disable virtual CD-ROM drive with built in software on Huawei and ZTE GSM modem devices|website=TechyTalk.info|access-date=2021-01-04}}</ref>{{failed verification|date=August 2024}}{{Unreliable source|1=|certain=y|date=August 2024}}

Available software utilities include the following:

* ZeroCD: When a device uses the ZeroCD method means that it behaves as a USB CD-ROM when first connected, with a virtual CD-ROM inserted with the Windows device drivers and related Cosmote control program. Once the Windows device drivers are installed, a special USB command is sent to the device to “switch” it to modem mode.<ref>{{cite web|title=ZTE MF636 (Cosmote 3G USB Modem in Greece) & Linux|date=5 November 2009|access-date=2019-02-10|url=http://stoilis.wordpress.com/2009/05/11/zte-mf636-cosmote-3g-usb-modem-in-greece-linux/|archive-url=https://web.archive.org/web/20100109115532/http://stoilis.wordpress.com/2009/05/11/zte-mf636-cosmote-3g-usb-modem-in-greece-linux/|archive-date=2010-01-09}}</ref>{{Unreliable source|1=|certain=y|date=August 2024}}

* Ozerocdoff: It temporarily disables ZeroCD for USB Option WWAN modem. The new USB Option WWAN modem devices support a CD-ROM device, which holds the needed Windows device driver to use the WWAN modem. Therefore, the firmware of the WWAN modem announces during the USB enumeration process to work as a virtual CD-ROM device with its vendor name "ZOPTION". This device is now called ZERO-CD. Ozerocdoff is a solution to switch off the ZERO-CD and allow the modem to be a used as a modem.<ref>[http://packages.debian.org/sid/ozerocdoff Debian package ozerocdoff in sid]</ref> {{Citation needed|date=August 2024}}

* USB_ModeSwitch: It is a virtual CD-ROM switching utility. From version 1.0.3 upwards there is a simple framework for integrating the switching with [[udev]] (the device manager) to make it fully automatic.<ref name="usb_modeswitch"/>

* Switch2modem: It is designed{{by whom|date=May 2015}} for switching a 3G USB modem. The program works under [[OpenSolaris]].<ref>