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IRIX Installation Tools & Overlays 2001 May
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SGI IRIX Installation Tools & Overlays 2001 May - Disc 3.iso
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dmedia_eoe
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2001-04-16
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199 lines
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7. _D_A_T__A_u_d_i_o__S_u_p_p_o_r_t
This section describes changes, bug fixes, known problems,
and known documentation errors relating to the audio
capabilities of the SCSI DDS drive for IRIX workstations.
Starting with IRIX 6.3, subsystem _d_m_e_d_i_a__e_o_e._s_w._t_o_o_l_s
includes a new DAT playback/capture program called
ddddaaaattttppppllllaaaayyyyeeeerrrr. DDDDaaaattttppppllllaaaayyyyeeeerrrr provides a transport control panel
interface to the audio capabilities of a DAT tape drive
include a track scanning mechanism and convenient audio
capture utilities. It also provides a facility for building
a database of the contents of a tape, so that the tape's
tracks may be listed by name.
DDDDaaaattttppppllllaaaayyyyeeeerrrr does not have any recording capabilities. Users
can master DAT tapes by using the EEEExxxxppppoooorrrrtttt file menu option in
SSSSoooouuuunnnnddddTTTTrrrraaaacccckkkk.
DDDDaaaattttppppllllaaaayyyyeeeerrrr does not replace the application ddddaaaattttmmmmaaaannnn since
ddddaaaattttmmmmaaaannnn is currently the only way to "spot record" onto DAT
tapes.
_P_L_E_A_S_E _N_O_T_E that as of 6.5, DAT audio is no longer
officially supported.
7.1 _C_h_a_n_g_e_s__a_n_d__A_d_d_i_t_i_o_n_s
+o We have added support for DDS3 drives from Sony. These
drives have excellent audio capabilities without the
firmware problems exhibited in older drives.
7.2 _K_n_o_w_n__P_r_o_b_l_e_m_s__a_n_d__W_o_r_k_a_r_o_u_n_d_s
There are a number of firmware problems with the older DDS2
drives. They are also very sensitive to tape residue. We
strongly recommend frequent cleaning and the use of new tape
when possible (particularly for mastering).
+o Please note that datplayer does not work reliably with
the DDS2 drives.
+o DAT audio firmware problem: data tape at BOT.
Assume a DDS (data) tape (ie, a tape previously
recorded in data mode) is inserted in the DAT drive.
The drive will rewind the tape to logical BOT, which on
a data tape is different than physical BOT. If you
attempt to write audio data to the drive, it begins
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writing at logical BOT. When the tape is later re-
inserted into the drive, it is incorrectly recognized
as a data tape since DDS format data exists between
physical BOT and logical BOT.
Workaround: Check to see if the tape in the drive is
DDS media and at BOT. If so, in audio mode write a
frame of data to move the tape off logical BOT, then
issue a rewind. This will cause the tape to rewind
back to physical BOT.
+o DAT audio firmware problem: read position bug.
The DAT drive firmware incorrectly returns its position
via the MTGETAUDIO ioctl to the IRIX tape driver. There
are two modes to this behavior.
+o Immediately following a seek: Suppose you seek by
A-time (absolute time). Then MTGETAUDIO returns
the correct A-time, but incorrect P-time (program
time). Suppose you seek by P-time. Then MTGETAUDIO
returns the correct P-time, but incorrect A-time.
+o Following a read or write: Both A-time and P-time
are wrong.
Workaround: Read a frame from the tape and decode the
subcode information. This of course moves the tape, so
you may have to seek back to the previous location or
otherwise account for the resulting 1 frame difference
between the frame read and the new tape position.
+o DAT audio firmware problem: read delay bug.
If not used for 60 seconds, the DAT drive unloads the
tape from the heads. Once this happens, subsequent
reads will fail.
Workaround: Avoid 60 second delays between subsequent
operations.
+o Write following read: A write following a read is not
frame-accurate. It may go onto the tape several frames
too early, overwriting some of the data just read.
Workaround: None (because of the following bug).
+o DAT audio firmware problem: Write following seek.
A write following a seek is not frame-accurate. About
50% of the time, a write following a seek will go onto
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the tape a few frames early.
Workaround: None.