1RX(4) Kernel Interfaces Manual RX(4)
2
6 rx - DEC RX02 floppy disk
7
9 /sys/conf/SYSTEM:
10 NRX rx_units # RX02
11 /etc/dtab:
13 #Name Unit# Addr Vector Br Handler(s) # Comments
14 rx ? 177170 264 5 rxintr # rx02
15 major device number(s):
17 raw: 17
18 block: 8
19 minor device encoding:
20 bit 01 specifies drive: <rx_drive>
21 bit 02 specifies density: single: 0, double: 1
22
24 The rx device provides access to a DEC RX02 floppy disk unit with M8256
25 interface module (RX211 configuration). The RX02 uses 8-inch, single-
26 sided, soft-sectored floppy disks (with pre-formatted industry-standard
27 headers) in either single or double density.
28 Floppy disks handled by the RX02 contain 77 tracks, each with 26 sec‐
30 tors (for a total of 2,002 sectors). The sector size is 128 bytes for
31 single density, 256 bytes for double density. Single density disks are
32 compatible with the RX01 floppy disk unit and with IBM 3740 Series
33 Diskette 1 systems.
34 Files with minor device numbers 0 and 1 refer to drives 0 and 1 in sin‐
36 gle density mode; minor devices 2 and 3 refer to drives 0 and 1 in dou‐
37 ble density mode. The standard device names begin with ``rx'' followed
38 by the drive number and then a letter a-b for single and double density
39 access to the drive respectively. The character ? stands here for a
40 drive number in the range 0-1.
41 The block files access the disk via the system's normal buffering mech‐
43 anism and may be read and written without regard to physical disk
44 records. There is also a `raw' interface which provides for direct
45 transmission between the disk and the user's read or write buffer. A
46 single read or write call results in exactly one I/O operation and
47 therefore raw I/O is considerably more efficient when many words are
48 transmitted. The names of the raw files conventionally begin with an
49 extra `r.'
50 In raw I/O the buffer must begin on a word (even) boundary, and counts
52 should be a multiple of the disk's sector size (either 128 or 256 bytes
53 depending on selected density.) Likewise seek calls should specify a
54 multiple of the disk's sector size.
55 In addition to normal (`block' and `raw') i/o, the driver supports for‐
57 matting of disks for either density.
58
60 The rx driver does not support pseudo-disks (partitions). Each file
61 rx?[ab] refers to the entire drive as a single sequentially addressed
62 file. The physical disk sector size is 128 bytes for single density
63 and 256 bytes for double density. The logical block size is 1024
64 bytes. Each diskette has 250 logical blocks in single density and 500
65 logical blocks in double density.
66 The size and density of the disks are specified as follows:
68 disk minor device unit density
70 rx0a 0 0 single
71 rx1a 1 1 single
72 rx0b 2 0 double
73 rx1b 3 1 double
74 Even though the storage capacity on a floppy disk is quite small, it is
76 possible to make file systems on them. For example, the commands
77 % rxformat /dev/rrx0a
78 % newfs /dev/rrx0a
79 and
80 % rxformat /dev/rrx1b
81 % newfs /dev/rrx1b
82 format and make file systems on the single density disk in the left
83 drive and the double density disk in the right drive with 241 and 486
84 kbytes available, respectively, for file storage. Using tar(1) gives
85 somewhat more efficient utilization of the available space for file
86 storage. The RX02 disks are primarily useful for small archives and
87 transfer of small systems or distributions.
88 An ioctl(2) call is available is available to format RX02 disks:
90 #include <pdpuba/rxreg.h>
91 ioctl(fildes, RXIOC_FORMAT)
92 The density is determined by the device opened.
93
95 /dev/rx[01][ab] block files
96 /dev/rrx[01][ab] raw files
97 /dev/MAKEDEV script to create special files
98 /dev/MAKEDEV.local script to localize special files
99
101 hk(4), ra(4), ram(4), rk(4), rl(4), rp(4), si(4), xp(4), dtab(5), auto‐
102 config(8), rxformat(8V)
103
105 rx2%d: hard error sn%d cs=%b er=%b. An unrecoverable error occurred
106 during transfer of the specified sector of the specified disk. The
107 contents of the two error registers are also printed in octal and sym‐
108 bolically with bits decoded. The error was either unrecoverable, or a
109 large number of retry attempts could not recover the error.
110
112 In raw I/O read and write(2) truncate file offsets to disk sector size
113 block boundaries (either 128 or 256 bytes depending on the selected
114 density), and write scribbles on the tail of incomplete blocks. Thus,
115 in programs that are likely to access raw devices, read, write and
116 lseek(2) should always deal in disk sector size multiples.
117 DEC-standard error logging should be supported.
119 A program to analyze the logged error information (even in its present
121 reduced form) is needed.
122 The 4.3BSD rx driver which supports more capabilities should be ported
124 to 2.11BSD.
1253rd Berkeley Distribution January 27, 1996 RX(4)