diff options
author | Heiko Carstens <heiko.carstens@de.ibm.com> | 2019-07-25 03:21:47 -0400 |
---|---|---|
committer | Vasily Gorbik <gor@linux.ibm.com> | 2019-08-21 06:41:42 -0400 |
commit | 8c72e0c85212df4e7c77fca55556e423fe17e801 (patch) | |
tree | 26fedaa9d519634d95ae58e7dc9b2f3bcdfde6ed | |
parent | 7c4e91c0959bf42a86ba4887425fc944d0d28595 (diff) |
Documentation/s390: remove outdated dasd documentation
The contents of the file is completely outdated - just remove it.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
-rw-r--r-- | Documentation/s390/dasd.rst | 84 | ||||
-rw-r--r-- | Documentation/s390/index.rst | 1 |
2 files changed, 0 insertions, 85 deletions
diff --git a/Documentation/s390/dasd.rst b/Documentation/s390/dasd.rst deleted file mode 100644 index 9e22247285c8..000000000000 --- a/Documentation/s390/dasd.rst +++ /dev/null | |||
@@ -1,84 +0,0 @@ | |||
1 | ================== | ||
2 | DASD device driver | ||
3 | ================== | ||
4 | |||
5 | S/390's disk devices (DASDs) are managed by Linux via the DASD device | ||
6 | driver. It is valid for all types of DASDs and represents them to | ||
7 | Linux as block devices, namely "dd". Currently the DASD driver uses a | ||
8 | single major number (254) and 4 minor numbers per volume (1 for the | ||
9 | physical volume and 3 for partitions). With respect to partitions see | ||
10 | below. Thus you may have up to 64 DASD devices in your system. | ||
11 | |||
12 | The kernel parameter 'dasd=from-to,...' may be issued arbitrary times | ||
13 | in the kernel's parameter line or not at all. The 'from' and 'to' | ||
14 | parameters are to be given in hexadecimal notation without a leading | ||
15 | 0x. | ||
16 | If you supply kernel parameters the different instances are processed | ||
17 | in order of appearance and a minor number is reserved for any device | ||
18 | covered by the supplied range up to 64 volumes. Additional DASDs are | ||
19 | ignored. If you do not supply the 'dasd=' kernel parameter at all, the | ||
20 | DASD driver registers all supported DASDs of your system to a minor | ||
21 | number in ascending order of the subchannel number. | ||
22 | |||
23 | The driver currently supports ECKD-devices and there are stubs for | ||
24 | support of the FBA and CKD architectures. For the FBA architecture | ||
25 | only some smart data structures are missing to make the support | ||
26 | complete. | ||
27 | We performed our testing on 3380 and 3390 type disks of different | ||
28 | sizes, under VM and on the bare hardware (LPAR), using internal disks | ||
29 | of the multiprise as well as a RAMAC virtual array. Disks exported by | ||
30 | an Enterprise Storage Server (Seascape) should work fine as well. | ||
31 | |||
32 | We currently implement one partition per volume, which is the whole | ||
33 | volume, skipping the first blocks up to the volume label. These are | ||
34 | reserved for IPL records and IBM's volume label to assure | ||
35 | accessibility of the DASD from other OSs. In a later stage we will | ||
36 | provide support of partitions, maybe VTOC oriented or using a kind of | ||
37 | partition table in the label record. | ||
38 | |||
39 | Usage | ||
40 | ===== | ||
41 | |||
42 | -Low-level format (?CKD only) | ||
43 | For using an ECKD-DASD as a Linux harddisk you have to low-level | ||
44 | format the tracks by issuing the BLKDASDFORMAT-ioctl on that | ||
45 | device. This will erase any data on that volume including IBM volume | ||
46 | labels, VTOCs etc. The ioctl may take a `struct format_data *` or | ||
47 | 'NULL' as an argument:: | ||
48 | |||
49 | typedef struct { | ||
50 | int start_unit; | ||
51 | int stop_unit; | ||
52 | int blksize; | ||
53 | } format_data_t; | ||
54 | |||
55 | When a NULL argument is passed to the BLKDASDFORMAT ioctl the whole | ||
56 | disk is formatted to a blocksize of 1024 bytes. Otherwise start_unit | ||
57 | and stop_unit are the first and last track to be formatted. If | ||
58 | stop_unit is -1 it implies that the DASD is formatted from start_unit | ||
59 | up to the last track. blksize can be any power of two between 512 and | ||
60 | 4096. We recommend no blksize lower than 1024 because the ext2fs uses | ||
61 | 1kB blocks anyway and you gain approx. 50% of capacity increasing your | ||
62 | blksize from 512 byte to 1kB. | ||
63 | |||
64 | Make a filesystem | ||
65 | ================= | ||
66 | |||
67 | Then you can mk??fs the filesystem of your choice on that volume or | ||
68 | partition. For reasons of sanity you should build your filesystem on | ||
69 | the partition /dev/dd?1 instead of the whole volume. You only lose 3kB | ||
70 | but may be sure that you can reuse your data after introduction of a | ||
71 | real partition table. | ||
72 | |||
73 | Bugs | ||
74 | ==== | ||
75 | |||
76 | - Performance sometimes is rather low because we don't fully exploit clustering | ||
77 | |||
78 | TODO-List | ||
79 | ========= | ||
80 | |||
81 | - Add IBM'S Disk layout to genhd | ||
82 | - Enhance driver to use more than one major number | ||
83 | - Enable usage as a module | ||
84 | - Support Cache fast write and DASD fast write (ECKD) | ||
diff --git a/Documentation/s390/index.rst b/Documentation/s390/index.rst index 4602312909d3..f8c01cb7fa37 100644 --- a/Documentation/s390/index.rst +++ b/Documentation/s390/index.rst | |||
@@ -15,7 +15,6 @@ s390 Architecture | |||
15 | vfio-ap | 15 | vfio-ap |
16 | vfio-ccw | 16 | vfio-ccw |
17 | zfcpdump | 17 | zfcpdump |
18 | dasd | ||
19 | common_io | 18 | common_io |
20 | 19 | ||
21 | text_files | 20 | text_files |