CedarBackup3.writers.cdwriter.CdWriter

Package CedarBackup3 :: Package writers :: Module cdwriter :: Class CdWriter |
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# Class CdWriter

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    object --+
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            CdWriter

Class representing a device that knows how to write CD media.

# Summary

This is a class representing a device that knows how to write CD media. It provides common operations for the device, such as ejecting the media, writing an ISO image to the media, or checking for the current media capacity. It also provides a place to store device attributes, such as whether the device supports writing multisession discs, etc.

This class is implemented in terms of the `eject` and `cdrecord` programs, both of which should be available on most UN*X platforms.

# Image Writer Interface

The following methods make up the "image writer" interface shared with other kinds of writers (such as DVD writers):

      __init__
      initializeImage()
      addImageEntry()
      writeImage()
      setImageNewDisc()
      retrieveCapacity()
      getEstimatedImageSize()

Only these methods will be used by other Cedar Backup functionality that expects a compatible image writer.

The media attribute is also assumed to be available.

# Media Types

This class knows how to write to two different kinds of media, represented by the following constants:

- `MEDIA_CDR_74`: 74-minute CD-R media (650 MB capacity)
- `MEDIA_CDRW_74`: 74-minute CD-RW media (650 MB capacity)
- `MEDIA_CDR_80`: 80-minute CD-R media (700 MB capacity)
- `MEDIA_CDRW_80`: 80-minute CD-RW media (700 MB capacity)

Most hardware can read and write both 74-minute and 80-minute CD-R and CD-RW media. Some older drives may only be able to write CD-R media. The difference between the two is that CD-RW media can be rewritten (erased), while CD-R media cannot be.

I do not support any other configurations for a couple of reasons. The first is that I've never tested any other kind of media. The second is that anything other than 74 or 80 minute is apparently non-standard.

# Device Attributes vs. Media Attributes

A given writer instance has two different kinds of attributes associated with it, which I call device attributes and media attributes. Device attributes are things which can be determined without looking at the media, such as whether the drive supports writing multisession disks or has a tray. Media attributes are attributes which vary depending on the state of the media, such as the remaining capacity on a disc. In general, device attributes are available via instance variables and are constant over the life of an object, while media attributes can be retrieved through method calls.

# Talking to Hardware

This class needs to talk to CD writer hardware in two different ways: through cdrecord to actually write to the media, and through the filesystem to do things like open and close the tray.

Historically, CdWriter has interacted with cdrecord using the scsiId attribute, and with most other utilities using the device attribute. This changed somewhat in Cedar Backup 2.9.0.

When Cedar Backup was first written, the only way to interact with cdrecord was by using a SCSI device id. IDE devices were mapped to pseudo-SCSI devices through the kernel. Later, extended SCSI "methods" arrived, and it became common to see `ATA:1,0,0` or `ATAPI:0,0,0` as a way to address IDE hardware. By late 2006, `ATA` and `ATAPI` had apparently been deprecated in favor of just addressing the IDE device directly by name, i.e. `/dev/cdrw`.

Because of this latest development, it no longer makes sense to require a CdWriter to be created with a SCSI id -- there might not be one. So, the passed-in SCSI id is now optional. Also, there is now a hardwareId attribute. This attribute is filled in with either the SCSI id (if provided) or the device (otherwise). The hardware id is the value that will be passed to cdrecord in the `dev=` argument.

# Testing

It's rather difficult to test this code in an automated fashion, even if you have access to a physical CD writer drive. It's even more difficult to test it if you are running on some build daemon (think of a Debian autobuilder) which can't be expected to have any hardware or any media that you could write to.

Because of this, much of the implementation below is in terms of static methods that are supposed to take defined actions based on their arguments. Public methods are then implemented in terms of a series of calls to simplistic static methods. This way, we can test as much as possible of the functionality via testing the static methods, while hoping that if the static methods are called appropriately, things will work properly. It's not perfect, but it's much better than no testing at all.

Instance Methods | [hide private]
__init__(self, device, scsiId=None, driveSpeed=None, mediaType=1, noEject=False, refreshMediaDelay=0, ejectDelay=0, unittest=False) Initializes a CD writer object. | source code
isRewritable(self) Indicates whether the media is rewritable per configuration. | source code
_retrieveProperties(self) Retrieves properties for a device from `cdrecord`. | source code
retrieveCapacity(self, entireDisc=False, useMulti=True) Retrieves capacity for the current media in terms of a `MediaCapacity` object. | source code
_getBoundaries(self, entireDisc=False, useMulti=True) Gets the ISO boundaries for the media. | source code
openTray(self) Opens the device's tray and leaves it open. | source code
closeTray(self) Closes the device's tray. | source code
refreshMedia(self) Opens and then immediately closes the device's tray, to refresh the device's idea of the media. | source code
writeImage(self, imagePath=None, newDisc=False, writeMulti=True) Writes an ISO image to the media in the device. | source code
_blankMedia(self) Blanks the media in the device, if the media is rewritable. | source code
initializeImage(self, newDisc, tmpdir, mediaLabel=None) Initializes the writer's associated ISO image. | source code
addImageEntry(self, path, graftPoint) Adds a filepath entry to the writer's associated ISO image. | source code
setImageNewDisc(self, newDisc) Resets (overrides) the newDisc flag on the internal image. | source code
getEstimatedImageSize(self) Gets the estimated size of the image associated with the writer. | source code
_getDevice(self) Property target used to get the device value. | source code
_getScsiId(self) Property target used to get the SCSI id value. | source code
_getHardwareId(self) Property target used to get the hardware id value. | source code
_getDriveSpeed(self) Property target used to get the drive speed. | source code
_getMedia(self) Property target used to get the media description. | source code
_getDeviceType(self) Property target used to get the device type. | source code
_getDeviceVendor(self) Property target used to get the device vendor. | source code
_getDeviceId(self) Property target used to get the device id. | source code
_getDeviceBufferSize(self) Property target used to get the device buffer size. | source code
_getDeviceSupportsMulti(self) Property target used to get the device-support-multi flag. | source code
_getDeviceHasTray(self) Property target used to get the device-has-tray flag. | source code
_getDeviceCanEject(self) Property target used to get the device-can-eject flag. | source code
_getRefreshMediaDelay(self) Property target used to get the configured refresh media delay, in seconds. | source code
_getEjectDelay(self) Property target used to get the configured eject delay, in seconds. | source code
unlockTray(self) Unlocks the device's tray. | source code
_createImage(self) Creates an ISO image based on configuration in self._image. | source code
_writeImage(self, imagePath, writeMulti, newDisc) Write an ISO image to disc using cdrecord. | source code
Inherited from `object`: `__delattr__`, `__format__`, `__getattribute__`, `__hash__`, `__new__`, `__reduce__`, `__reduce_ex__`, `__repr__`, `__setattr__`, `__sizeof__`, `__str__`, `__subclasshook__`

Static Methods | [hide private]
_calculateCapacity(media, boundaries) Calculates capacity for the media in terms of boundaries. | source code
_parsePropertiesOutput(output) Parses the output from a `cdrecord` properties command. | source code
_parseBoundariesOutput(output) Parses the output from a `cdrecord` capacity command. | source code
_buildOpenTrayArgs(device) Builds a list of arguments to be passed to a `eject` command. | source code
_buildCloseTrayArgs(device) Builds a list of arguments to be passed to a `eject` command. | source code
_buildPropertiesArgs(hardwareId) Builds a list of arguments to be passed to a `cdrecord` command. | source code
_buildBoundariesArgs(hardwareId) Builds a list of arguments to be passed to a `cdrecord` command. | source code
_buildBlankArgs(hardwareId, driveSpeed=None) Builds a list of arguments to be passed to a `cdrecord` command. | source code
_buildWriteArgs(hardwareId, imagePath, driveSpeed=None, writeMulti=True) Builds a list of arguments to be passed to a `cdrecord` command. | source code
_buildUnlockTrayArgs(device) Builds a list of arguments to be passed to a `eject` command. | source code

Properties | [hide private]
| device Filesystem device name for this writer.
| scsiId SCSI id for the device, in the form `[<method>:]scsibus,target,lun`.
| hardwareId Hardware id for this writer, either SCSI id or device path.
| driveSpeed Speed at which the drive writes.
| media Definition of media that is expected to be in the device.
| deviceType Type of the device, as returned from `cdrecord -prcap`.
| deviceVendor Vendor of the device, as returned from `cdrecord -prcap`.
| deviceId Device identification, as returned from `cdrecord -prcap`.
| deviceBufferSize Size of the device's write buffer, in bytes.
| deviceSupportsMulti Indicates whether device supports multisession discs.
| deviceHasTray Indicates whether the device has a media tray.
| deviceCanEject Indicates whether the device supports ejecting its media.
| refreshMediaDelay Refresh media delay, in seconds.
| ejectDelay Eject delay, in seconds.
Inherited from `object`: `__class__`

Method Details | [hide private]

### __init__(self, device, scsiId=None, driveSpeed=None, mediaType=1, noEject=False, refreshMediaDelay=0, ejectDelay=0, unittest=False) (Constructor) | source code
Initializes a CD writer object. The current user must have write access to the device at the time the object is instantiated, or an exception will be thrown. However, no media-related validation is done, and in fact there is no need for any media to be in the drive until one of the other media attribute-related methods is called. The various instance variables such as `deviceType`, `deviceVendor`, etc. might be `None`, if we're unable to parse this specific information from the `cdrecord` output. This information is just for reference. The SCSI id is optional, but the device path is required. If the SCSI id is passed in, then the hardware id attribute will be taken from the SCSI id. Otherwise, the hardware id will be taken from the device. If cdrecord improperly detects whether your writer device has a tray and can be safely opened and closed, then pass in `noEject=False`. This will override the properties and the device will never be ejected. Parameters: `device` (Absolute path to a filesystem device, i.e. `/dev/cdrw`) - Filesystem device associated with this writer. `scsiId` (If provided, SCSI id in the form `[<method>:]scsibus,target,lun`) - SCSI id for the device (optional). `driveSpeed` (Use `2` for 2x device, etc. or `None` to use device default.) - Speed at which the drive writes. `mediaType` (One of the valid media type as discussed above.) - Type of the media that is assumed to be in the drive. `noEject` (Boolean true/false) - Overrides properties to indicate that the device does not support eject. `refreshMediaDelay` (Number of seconds, an integer >= 0) - Refresh media delay to use, if any `ejectDelay` (Number of seconds, an integer >= 0) - Eject delay to use, if any `unittest` (Boolean true/false) - Turns off certain validations, for use in unit testing. Raises: `ValueError` - If the device is not valid for some reason. `ValueError` - If the SCSI id is not in a valid form. `ValueError` - If the drive speed is not an integer >= 1. `IOError` - If device properties could not be read for some reason. Overrides: object.__init__ Note: The `unittest` parameter should never be set to `True` outside of Cedar Backup code. It is intended for use in unit testing Cedar Backup internals and has no other sensible purpose.

### _retrieveProperties(self) | source code
Retrieves properties for a device from `cdrecord`. The results are returned as a tuple of the object device attributes as returned from _parsePropertiesOutput: `(deviceType, deviceVendor, deviceId, deviceBufferSize, deviceSupportsMulti, deviceHasTray, deviceCanEject)`. Returns: Results tuple as described above. Raises: `IOError` - If there is a problem talking to the device.

### retrieveCapacity(self, entireDisc=False, useMulti=True) | source code
Retrieves capacity for the current media in terms of a `MediaCapacity` object. If `entireDisc` is passed in as `True` the capacity will be for the entire disc, as if it were to be rewritten from scratch. If the drive does not support writing multisession discs or if `useMulti` is passed in as `False`, the capacity will also be as if the disc were to be rewritten from scratch, but the indicated boundaries value will be `None`. The same will happen if the disc cannot be read for some reason. Otherwise, the capacity (including the boundaries) will represent whatever space remains on the disc to be filled by future sessions. Parameters: `entireDisc` (Boolean true/false) - Indicates whether to return capacity for entire disc. `useMulti` (Boolean true/false) - Indicates whether a multisession disc should be assumed, if possible. Returns: `MediaCapacity` object describing the capacity of the media. Raises: `IOError` - If the media could not be read for some reason.

### _getBoundaries(self, entireDisc=False, useMulti=True) | source code
Gets the ISO boundaries for the media. If `entireDisc` is passed in as `True` the boundaries will be `None`, as if the disc were to be rewritten from scratch. If the drive does not support writing multisession discs, the returned value will be `None`. The same will happen if the disc can't be read for some reason. Otherwise, the returned value will be represent the boundaries of the disc's current contents. The results are returned as a tuple of (lower, upper) as needed by the `IsoImage` class. Note that these values are in terms of ISO sectors, not bytes. Clients should generally consider the boundaries value opaque, however. Parameters: `entireDisc` (Boolean true/false) - Indicates whether to return capacity for entire disc. `useMulti` (Boolean true/false) - Indicates whether a multisession disc should be assumed, if possible. Returns: Boundaries tuple or `None`, as described above. Raises: `IOError` - If the media could not be read for some reason.

### _calculateCapacity(media, boundaries) Static Method | source code
Calculates capacity for the media in terms of boundaries. If `boundaries` is `None` or the lower bound is 0 (zero), then the capacity will be for the entire disc minus the initial lead in. Otherwise, capacity will be as if the caller wanted to add an additional session to the end of the existing data on the disc. Parameters: `media` - MediaDescription object describing the media capacity. `boundaries` - Session boundaries as returned from _getBoundaries. Returns: `MediaCapacity` object describing the capacity of the media.

### openTray(self) | source code
Opens the device's tray and leaves it open. This only works if the device has a tray and supports ejecting its media. We have no way to know if the tray is currently open or closed, so we just send the appropriate command and hope for the best. If the device does not have a tray or does not support ejecting its media, then we do nothing. If the writer was constructed with `noEject=True`, then this is a no-op. Starting with Debian wheezy on my backup hardware, I started seeing consistent problems with the eject command. I couldn't tell whether these problems were due to the device management system or to the new kernel (3.2.0). Initially, I saw simple eject failures, possibly because I was opening and closing the tray too quickly. I worked around that behavior with the new ejectDelay flag. Later, I sometimes ran into issues after writing an image to a disc: eject would give errors like "unable to eject, last error: Inappropriate ioctl for device". Various sources online (like Ubuntu bug #875543) suggested that the drive was being locked somehow, and that the workaround was to run 'eject -i off' to unlock it. Sure enough, that fixed the problem for me, so now it's a normal error-handling strategy. Raises: `IOError` - If there is an error talking to the device.

### closeTray(self) | source code
Closes the device's tray. This only works if the device has a tray and supports ejecting its media. We have no way to know if the tray is currently open or closed, so we just send the appropriate command and hope for the best. If the device does not have a tray or does not support ejecting its media, then we do nothing. If the writer was constructed with `noEject=True`, then this is a no-op. Raises: `IOError` - If there is an error talking to the device.

### refreshMedia(self) | source code
Opens and then immediately closes the device's tray, to refresh the device's idea of the media. Sometimes, a device gets confused about the state of its media. Often, all it takes to solve the problem is to eject the media and then immediately reload it. (There are also configurable eject and refresh media delays which can be applied, for situations where this makes a difference.) This only works if the device has a tray and supports ejecting its media. We have no way to know if the tray is currently open or closed, so we just send the appropriate command and hope for the best. If the device does not have a tray or does not support ejecting its media, then we do nothing. The configured delays still apply, though. Raises: `IOError` - If there is an error talking to the device.

### writeImage(self, imagePath=None, newDisc=False, writeMulti=True) | source code
Writes an ISO image to the media in the device. If `newDisc` is passed in as `True`, we assume that the entire disc will be overwritten, and the media will be blanked before writing it if possible (i.e. if the media is rewritable). If `writeMulti` is passed in as `True`, then a multisession disc will be written if possible (i.e. if the drive supports writing multisession discs). if `imagePath` is passed in as `None`, then the existing image configured with `initializeImage` will be used. Under these circumstances, the passed-in `newDisc` flag will be ignored. By default, we assume that the disc can be written multisession and that we should append to the current contents of the disc. In any case, the ISO image must be generated appropriately (i.e. must take into account any existing session boundaries, etc.) Parameters: `imagePath` (String representing a path on disk) - Path to an ISO image on disk, or `None` to use writer's image `newDisc` (Boolean true/false.) - Indicates whether the entire disc will overwritten. `writeMulti` (Boolean true/false) - Indicates whether a multisession disc should be written, if possible. Raises: `ValueError` - If the image path is not absolute. `ValueError` - If some path cannot be encoded properly. `IOError` - If the media could not be written to for some reason. `ValueError` - If no image is passed in and initializeImage() was not previously called

### _blankMedia(self) | source code
Blanks the media in the device, if the media is rewritable. Raises: `IOError` - If the media could not be written to for some reason.

### _parsePropertiesOutput(output) Static Method | source code
Parses the output from a `cdrecord` properties command. The `output` parameter should be a list of strings as returned from `executeCommand` for a `cdrecord` command with arguments as from `_buildPropertiesArgs`. The list of strings will be parsed to yield information about the properties of the device. The output is expected to be a huge long list of strings. Unfortunately, the strings aren't in a completely regular format. However, the format of individual lines seems to be regular enough that we can look for specific values. Two kinds of parsing take place: one kind of parsing picks out out specific values like the device id, device vendor, etc. The other kind of parsing just sets a boolean flag `True` if a matching line is found. All of the parsing is done with regular expressions. Right now, pretty much nothing in the output is required and we should parse an empty document successfully (albeit resulting in a device that can't eject, doesn't have a tray and doesnt't support multisession discs). I had briefly considered erroring out if certain lines weren't found or couldn't be parsed, but that seems like a bad idea given that most of the information is just for reference. The results are returned as a tuple of the object device attributes: `(deviceType, deviceVendor, deviceId, deviceBufferSize, deviceSupportsMulti, deviceHasTray, deviceCanEject)`. Parameters: `output` - Output from a `cdrecord -prcap` command. Returns: Results tuple as described above. Raises: `IOError` - If there is problem parsing the output.

### _parseBoundariesOutput(output) Static Method | source code
Parses the output from a `cdrecord` capacity command. The `output` parameter should be a list of strings as returned from `executeCommand` for a `cdrecord` command with arguments as from `_buildBoundaryArgs`. The list of strings will be parsed to yield information about the capacity of the media in the device. Basically, we expect the list of strings to include just one line, a pair of values. There isn't supposed to be whitespace, but we allow it anyway in the regular expression. Any lines below the one line we parse are completely ignored. It would be a good idea to ignore `stderr` when executing the `cdrecord` command that generates output for this method, because sometimes `cdrecord` spits out kernel warnings about the actual output. The results are returned as a tuple of (lower, upper) as needed by the `IsoImage` class. Note that these values are in terms of ISO sectors, not bytes. Clients should generally consider the boundaries value opaque, however. Parameters: `output` - Output from a `cdrecord -msinfo` command. Returns: Boundaries tuple as described above. Raises: `IOError` - If there is problem parsing the output. Note: If the boundaries output can't be parsed, we return `None`.

### _buildOpenTrayArgs(device) Static Method | source code
Builds a list of arguments to be passed to a `eject` command. The arguments will cause the `eject` command to open the tray and eject the media. No validation is done by this method as to whether this action actually makes sense. Parameters: `device` - Filesystem device name for this writer, i.e. `/dev/cdrw`. Returns: List suitable for passing to util.executeCommand as `args`.

### _buildCloseTrayArgs(device) Static Method | source code
Builds a list of arguments to be passed to a `eject` command. The arguments will cause the `eject` command to close the tray and reload the media. No validation is done by this method as to whether this action actually makes sense. Parameters: `device` - Filesystem device name for this writer, i.e. `/dev/cdrw`. Returns: List suitable for passing to util.executeCommand as `args`.

### _buildPropertiesArgs(hardwareId) Static Method | source code
Builds a list of arguments to be passed to a `cdrecord` command. The arguments will cause the `cdrecord` command to ask the device for a list of its capacities via the `-prcap` switch. Parameters: `hardwareId` - Hardware id for the device (either SCSI id or device path) Returns: List suitable for passing to util.executeCommand as `args`.

### _buildBoundariesArgs(hardwareId) Static Method | source code
Builds a list of arguments to be passed to a `cdrecord` command. The arguments will cause the `cdrecord` command to ask the device for the current multisession boundaries of the media using the `-msinfo` switch. Parameters: `hardwareId` - Hardware id for the device (either SCSI id or device path) Returns: List suitable for passing to util.executeCommand as `args`.

### _buildBlankArgs(hardwareId, driveSpeed=None) Static Method | source code
Builds a list of arguments to be passed to a `cdrecord` command. The arguments will cause the `cdrecord` command to blank the media in the device identified by `hardwareId`. No validation is done by this method as to whether the action makes sense (i.e. to whether the media even can be blanked). Parameters: `hardwareId` - Hardware id for the device (either SCSI id or device path) `driveSpeed` - Speed at which the drive writes. Returns: List suitable for passing to util.executeCommand as `args`.

### _buildWriteArgs(hardwareId, imagePath, driveSpeed=None, writeMulti=True) Static Method | source code
Builds a list of arguments to be passed to a `cdrecord` command. The arguments will cause the `cdrecord` command to write the indicated ISO image (`imagePath`) to the media in the device identified by `hardwareId`. The `writeMulti` argument controls whether to write a multisession disc. No validation is done by this method as to whether the action makes sense (i.e. to whether the device even can write multisession discs, for instance). Parameters: `hardwareId` - Hardware id for the device (either SCSI id or device path) `imagePath` - Path to an ISO image on disk. `driveSpeed` - Speed at which the drive writes. `writeMulti` - Indicates whether to write a multisession disc. Returns: List suitable for passing to util.executeCommand as `args`.

### initializeImage(self, newDisc, tmpdir, mediaLabel=None) | source code
Initializes the writer's associated ISO image. This method initializes the `image` instance variable so that the caller can use the `addImageEntry` method. Once entries have been added, the `writeImage` method can be called with no arguments. Parameters: `newDisc` (Boolean true/false.) - Indicates whether the disc should be re-initialized `tmpdir` (String representing a directory path on disk) - Temporary directory to use if needed `mediaLabel` (String, no more than 25 characters long) - Media label to be applied to the image, if any

### addImageEntry(self, path, graftPoint) | source code
Adds a filepath entry to the writer's associated ISO image. The contents of the filepath -- but not the path itself -- will be added to the image at the indicated graft point. If you don't want to use a graft point, just pass `None`. Parameters: `path` (String representing a path on disk) - File or directory to be added to the image `graftPoint` (String representing a graft point path, as described above) - Graft point to be used when adding this entry Raises: `ValueError` - If initializeImage() was not previously called Note: Before calling this method, you must call initializeImage.

### setImageNewDisc(self, newDisc) | source code
Resets (overrides) the newDisc flag on the internal image. Parameters: `newDisc` - New disc flag to set Raises: `ValueError` - If initializeImage() was not previously called

### getEstimatedImageSize(self) | source code
Gets the estimated size of the image associated with the writer. Returns: Estimated size of the image, in bytes. Raises: `IOError` - If there is a problem calling `mkisofs`. `ValueError` - If initializeImage() was not previously called

### unlockTray(self) | source code
Unlocks the device's tray. Raises: `IOError` - If there is an error talking to the device.

### _createImage(self) | source code
Creates an ISO image based on configuration in self._image. Returns: Path to the newly-created ISO image on disk. Raises: `IOError` - If there is an error writing the image to disk. `ValueError` - If there are no filesystem entries in the image `ValueError` - If a path cannot be encoded properly.

### _writeImage(self, imagePath, writeMulti, newDisc) | source code
Write an ISO image to disc using cdrecord. The disc is blanked first if `newDisc` is `True`. Parameters: `imagePath` - Path to an ISO image on disk `writeMulti` - Indicates whether a multisession disc should be written, if possible. `newDisc` - Indicates whether the entire disc will overwritten.

### _buildUnlockTrayArgs(device) Static Method | source code
Builds a list of arguments to be passed to a `eject` command. The arguments will cause the `eject` command to unlock the tray. Parameters: `device` - Filesystem device name for this writer, i.e. `/dev/cdrw`. Returns: List suitable for passing to util.executeCommand as `args`.

Property Details | [hide private]

### device Filesystem device name for this writer. Get Method: _getDevice(self) - Property target used to get the device value.

### scsiId SCSI id for the device, in the form `[<method>:]scsibus,target,lun`. Get Method: _getScsiId(self) - Property target used to get the SCSI id value.

### hardwareId Hardware id for this writer, either SCSI id or device path. Get Method: _getHardwareId(self) - Property target used to get the hardware id value.

### driveSpeed Speed at which the drive writes. Get Method: _getDriveSpeed(self) - Property target used to get the drive speed.

### media Definition of media that is expected to be in the device. Get Method: _getMedia(self) - Property target used to get the media description.

### deviceType Type of the device, as returned from `cdrecord -prcap`. Get Method: _getDeviceType(self) - Property target used to get the device type.

### deviceVendor Vendor of the device, as returned from `cdrecord -prcap`. Get Method: _getDeviceVendor(self) - Property target used to get the device vendor.

### deviceId Device identification, as returned from `cdrecord -prcap`. Get Method: _getDeviceId(self) - Property target used to get the device id.

### deviceBufferSize Size of the device's write buffer, in bytes. Get Method: _getDeviceBufferSize(self) - Property target used to get the device buffer size.

### deviceSupportsMulti Indicates whether device supports multisession discs. Get Method: _getDeviceSupportsMulti(self) - Property target used to get the device-support-multi flag.

### deviceHasTray Indicates whether the device has a media tray. Get Method: _getDeviceHasTray(self) - Property target used to get the device-has-tray flag.

### deviceCanEject Indicates whether the device supports ejecting its media. Get Method: _getDeviceCanEject(self) - Property target used to get the device-can-eject flag.

### refreshMediaDelay Refresh media delay, in seconds. Get Method: _getRefreshMediaDelay(self) - Property target used to get the configured refresh media delay, in seconds.

### ejectDelay Eject delay, in seconds. Get Method: _getEjectDelay(self) - Property target used to get the configured eject delay, in seconds.