term% allow
term% echo quickblank > /dev/sdC1/ctl
echo: write error: bad process or channel control request
term% mntcd
mount: can't open /srv/9660: '/srv/9660' file does not exist
ERROR\n
term% /bin/mntcd
/n/cd/Unix
term% echo quickblank > /dev/sdC1/ctl
echo: write error: bad process or channel control request
term% cat  /dev/sdC1/ctl
inquiry HP      CD-Writer+ 7200 3.014VO09984119221600210
config 8580 capabilities 0B00
term% echo dma on >  /dev/sdC1/ctl
echo: write error: bad process or channel control request
term% allow
term% echo dma on >  /dev/sdC1/ctl
echo: write error: bad process or channel control request
term% um # unmount all
term% echo dma on >  /dev/sdC1/ctl
echo: write error: bad process or channel control request
term%