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diff --git a/static/unix-v10/man4/ra.4 b/static/unix-v10/man4/ra.4 new file mode 100644 index 00000000..a211ebad --- /dev/null +++ b/static/unix-v10/man4/ra.4 @@ -0,0 +1,218 @@ +.TH RA 4 +.CT 2 sa +.SH NAME +ra \- DEC MSCP disks (RA60, RA80, RA81, RA90) +.SH DESCRIPTION +.I Ra +devices occupy disk drives conforming to +DEC's Mass Storage Control Protocol standard: +drives such as the RA81 +connected via controllers such as the UDA50. +Files with minor device numbers 0 through 7 +refer to different sections of drive 0, +minor devices 8 through 16 refer to drive 1, +and so on up to 63 (8 drives). +.PP +Normally the disk is accessed in 1024-byte blocks (1K). +If 64 is added to the minor device number, +4096-byte blocks (4K) are used instead. +A 4K device mounted as a file system is bitmapped; see +.IR filsys (5). +.PP +Conventionally the files are given names like +.L ra37 +for section 7 of drive 3. +There are no name rules distinguishing 1024-byte files +from 4096-byte files; +in practice the files are almost always the 4096-byte kind. +.PP +The start and size +of the sections of each drive +are as follows. +Sizes are measured in +512-byte hardware sectors. +.PP +.nf +.ta .5i +\w'000000 'u +\w'000000 'u + disk start length + 0 0 10240 + 1 10240 20480 + 2 30720 249848 + 3 280568 249848 + 4 530416 249848 + 5 780264 arbitrarily large + 6 30720 749544 + 7 0 arbitrarily large +.DT +.fi +.PP +The `arbitrarily large' +sections reach to the end of the disk. +.I Rarct +will display disk sizes; see +.IR rarepl (8). +For example, +an RA81 has 891072 sectors, +so section 7 is that size, +and section 5 is +891072\(mi780264=110808 sectors. +An RA90 has 2376153 sectors; +section 7 is that size, +section 5 is +2376153\(mi780264=1595889 sectors. +For other disks, +run +.I rarct +and do the arithmetic. +.PP +The +.I ra +files +discussed above access the disk via the system's normal +buffering mechanism +and may be read and written without regard to +physical disk records. +There is also a `raw' interface +which provides for direct transmission between the disk +and the user's read or write buffer. +A single read or write call results in exactly one I/O operation +and therefore raw I/O is considerably more efficient when +many words are transmitted. +The names of the raw files +begin with +.L rra +and end with a number which selects the same disk +as the corresponding +.L ra +file. +.PP +In raw I/O the buffer must begin on a word boundary, +and counts should be a multiple of 512 bytes +(a disk block). +Likewise +.IR lseek (2) +calls should specify a multiple of 512 bytes. +.PP +Several +.IR ioctl (2) +calls +apply to the raw devices. +.TF UIORRCT +.TP +.B UIOCHAR +The third argument to +.I ioctl +points to an object +to be filled with drive parameters: +.EX +.ta .5i +\w'daddr_t 'u +\w'radsize 'u +struct ud_unit { + daddr_t radsize; /* disk size, sectors */ + daddr_t rctsize; /* RCT size, including pad */ + long medium; /* medium id */ + short tracksz; /* sectors per track */ + short groupsz; /* tracks per group */ + short cylsz; /* groups per cylinder */ + char rbns; /* RBNs per track */ + char copies; /* number of RCT copies */ +}; +.EE +.TF UIORRCT +.TP +.B UIORRCT +The third argument points to an object of type +.EX +struct ud_rctbuf { + caddr_t buf; + int lbn; +}; +.EE +.IP +.B buf +points to a 512-byte buffer, +into which block +.B lbn +of the replacement and caching table +(RCT) +is read. +As many copies of the RCT +as necessary +are examined to find a readable copy +of the block. +.TP +.B UIOWRCT +The third argument is like that of +.BR UIORRCT . +Block +.B lbn +of the RCT is written +in all copies. +.TP +.B UIOREPL +The third argument points to an object of type: +.EX +struct ud_repl { + daddr_t replbn; /* good block */ + daddr_t lbn; /* bad block */ + short prim; /* nonzero if primary replacement */ +}; +.EE +.IP +A `replace' command +is sent to the controller, +requesting that attempts to access logical block +.I lbn +henceforth be revectored to replacement block +.IR replbn . +.I Prim +should be set nonzero +if and only if +.I replbn +is the primary replacement block for +.IR lbn . +.TP +.B UIOSPDW +Arrange that the disk drive will spin down +when the last file using it is closed. +.TP +.B UIORST +Reset the controller +to which this disk is connected. +Any pending operations are abandoned and return an error. +.SH FILES +.F /dev/ra* +.br +.F /dev/rra* +.SH SEE ALSO +.IR rarepl (8) +.br +MSCP Basic Disk Functions Manual +.br +DEC Standard Disk Format Specification +.SH BUGS +In raw I/O +.IR read (2) +and +.IR write +truncate file offsets to 512-byte block boundaries, +and +.I write +scribbles on the tail of incomplete blocks. +Thus, +in programs that are likely to access raw devices, +.I read, write +and +.IR lseek (2) +should always deal in 512-byte multiples. +.PP +.B UIORRCT +and +.B UIOWRCT +will misbehave if invoked on a section +that doesn't start +at the beginning of the disk. +Section 7 +(the whole disk) +is the best choice. +.PP +The 1K/4K flag bit in the device number is unfortunate. |