I read a tutorial about writing a bootloader. The author gave this as an example of a boot parameter block:
bootsector:
iOEM: .ascii "DevOS " # OEM String
iSectSize: .word 0x200 # bytes per sector
iClustSize: .byte 1 # sectors per cluster
iResSect: .word 1 # #of reserved sectors
iFatCnt: .byte 2 # #of FAT copies
iRootSize: .word 224 # size of root directory
iTotalSect: .word 2880 # total # of sectors if over 32 MB
iMedia: .byte 0xF0 # media Descriptor
iFatSize: .word 9 # size of each FAT
iTrackSect: .word 9 # sectors per track
iHeadCnt: .word 2 # number of read-write heads
iHiddenSect: .int 0 # number of hidden sectors
iSect32: .int 0 # # sectors for over 32 MB
iBootDrive: .byte 0 # holds drive that the boot sector came from
iReserved: .byte 0 # reserved, empty
iBootSign: .byte 0x29 # extended boot sector signature
iVolID: .ascii "seri" # disk serial
acVolumeLabel: .ascii "MYVOLUME " # volume label
acFSType: .ascii "FAT16 " # file system type
If I am using a FAT32 file system can I just change the last part (acFSType: ascii “FAT16 “) and use this boot parameter block? If not where can I get a boot parameter block for FAT32?
I asked Mike Saunders ( the author of Mike-OS) in an email and his answer was no. I can't use this table for FAT32 just by changing that (acFSType: ascii “FAT16 “)part. To get a boot parameter block for the FAT32 file-system he sent me this link to the Microsoft website.
Related
As you can see in the below command I have assigned a total of 500 GB disk space to my VM. But I am seeing 14.4 GB actual space available to the disk and once it gets used completely. I got an error there isn't much space to use? How to extend space for /dev/mapper/centos-root.
I am using VMware ESXi and using centOS for this VM.
[root#localhost Apr]# fdisk -l
Disk /dev/sda: 536.9 GB, 536870912000 bytes, 1048576000 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x00064efd
Device Boot Start End Blocks Id System
/dev/sda1 * 2048 2099199 1048576 83 Linux
/dev/sda2 2099200 33554431 15727616 8e Linux LVM
Disk /dev/mapper/centos-root: 14.4 GB, 14382268416 bytes, 28090368 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/mapper/centos-swap: 1719 MB, 1719664640 bytes, 3358720 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 byte
Execute bellow Steps to increase your Linux Disk after adding space in VMWare :
Step 1 - update partition table
fdisk /dev/sda
Press p to print the partition table to identify the number of partitions.
Press n to create a new primary partition.
Press p for primary.
Press 3 for the partition number, depending on the output of the partition table print.
Press Enter two times.
Press t to change the system's partition ID.
Press 3 to select the newly creation partition.
Type 8e to change the Hex Code of the partition for Linux LVM.
Press w to write the changes to the partition table.
Step 2 - Restart the virtual machine.
Step 3 - verify that the changes were saved
fdisk -l
Step 4 - convert the new partition to a physical volume
pvcreate /dev/sda3
Step 5 - extend the physical volume (centos is your VG name, if not use your VG name in place of centos )
vgextend centos /dev/sda3
Step 6 - extend the Logical Volume (500G is the size you want to add , if not use the right size in place of 500G)
lvextend -L+500G /dev/mapper/centos-root
Step 7 - expand the ext filesystem online
resize2fs /dev/mapper/centos-root
extend disk without reboot
echo 1 > /sys/block/sda/device/rescan
echo 1 > /sys/block/sdb/device/rescan
echo 1 > /sys/block/nvme0n1/device/rescan_controller
partprobe
gdisk fix warnging
parted change partion size
## parted can executed as command line. but this is very dangerous
parted -s /dev/sdb "resizepart 2 -1" quit
parted -s /dev/sdb "resizepart 3 100%" quit
resizepart 3 100%
pvresize /dev/sda3
lvextend -l +100%FREE cs/root
xfs_growfs /dev/cs/root
I am very newbie in OrangePI PC. I have installed it by dd on my macOS, and I have tried installing a Raspbian image which downloaded from the orangepi.org in Windows as well, after installation when I check free disk space it is showing:
root#orangepi:~# df -h
Filesystem Size Used Avail Use% Mounted on
rootfs 3.4G 2.7G 474M 86% /
/dev/root 3.4G 2.7G 474M 86% /
devtmpfs 374M 0 374M 0% /dev
tmpfs 101M 188K 101M 1% /run
tmpfs 5.0M 0 5.0M 0% /run/lock
tmpfs 201M 0 201M 0% /run/shm
/dev/mmcblk0p1 41M 4.9M 37M 12% /boot
I have installed it on 32G flash drive. But when I check it through fdisk command it shows 32G as a disk size:
root#orangepi:~# sudo fdisk -l
Disk /dev/mmcblk0: 32.0 GB, 32010928128 bytes
4 heads, 16 sectors/track, 976896 cylinders, total 62521344 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x34605ba5
Device Boot Start End Blocks Id System
/dev/mmcblk0p1 40960 124927 41984 83 Linux
/dev/mmcblk0p2 124928 7170047 3522560 83 Linux
root#orangepi:~#
How to fix this?
This solved my problem (solution is taken from here):
root#orangepi:~# fdisk /dev/mmcblk0
Command (m for help): p
Disk /dev/mmcblk0: 15.8 GB, 15804137472 bytes
4 heads, 16 sectors/track, 482304 cylinders, total 30867456 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x34605ba5
Device Boot Start End Blocks Id System
/dev/mmcblk0p1 40960 124927 41984 83 Linux
/dev/mmcblk0p2 124928 7170047 3522560 83 Linux
Command (m for help): d
Partition number (1-4): 2
Command (m for help): n
Partition type:
p primary (1 primary, 0 extended, 3 free)
e extended
Select (default p): p
Partition number (1-4, default 2): 2
First sector (2048-30867455, default 2048): 124928
Last sector, +sectors or +size{K,M,G} (124928-30867455, default 30867455):
Using default value 30867455
Command (m for help): w
Then quit (command q), reboot. You will then be able to use resize:
resize2fs /dev/root
Good morning, this is what i get from apache error
Fatal Error Unable to allocate shared memory segment of 134217728 bytes: mmap: Cannot allocate memory (12)
This is my ipcs -lm
------ Limiti della memoria condivisa --------
max number of segments = 4096
max seg size (kbytes) = 131072
max total shared memory (kbytes) = 536870912
dimensione min seg (byte) = 1
This is cat /etc/sysctl.conf
# Controls the default maxmimum size of a mesage queue
# kernel.msgmnb = 65536
# Controls the maximum size of a message, in bytes
# kernel.msgmax = 65536
# Controls the maximum shared segment size, in bytes
# kernel.shmmax = 200000000
# Controls the maximum number of shared memory segments, in pages
# kernel.shmall = 50000
#
I've set unlimit to unlimited, and i've tryed all the things present on internet.
Can you please tell me what's wrong?
first of all,
please consider to remove # sign before
# kernel.shmmax = 200000000
# kernel.shmall = 50000
like this:
# Controls the maximum shared segment size, in bytes
kernel.shmmax = 200000000
# Controls the maximum number of shared memory segments, in pages
kernel.shmall = 50000
I'm trying to create a estimation of the size of a chain if i create a new blockchain using hyperldger.
In order to have an idea of disk space usage i would like to know that is the average size of a default block in the hyperldger fabric.
Thank you before hand,
Best Regards
Bellow you can find default configuration provided for ordering service. You can actually control block size with BatchTimeout and BatchSize parameters, also note that this is pretty use case dependent as it relies on transaction size, i.e. the logic of your chaincode.
################################################################################
#
# SECTION: Orderer
#
# - This section defines the values to encode into a config transaction or
# genesis block for orderer related parameters
#
################################################################################
Orderer: &OrdererDefaults
# Orderer Type: The orderer implementation to start
# Available types are "solo" and "kafka"
OrdererType: solo
Addresses:
- orderer.example.com:7050
# Batch Timeout: The amount of time to wait before creating a batch
BatchTimeout: 2s
# Batch Size: Controls the number of messages batched into a block
BatchSize:
# Max Message Count: The maximum number of messages to permit in a batch
MaxMessageCount: 10
# Absolute Max Bytes: The absolute maximum number of bytes allowed for
# the serialized messages in a batch.
AbsoluteMaxBytes: 98 MB
# Preferred Max Bytes: The preferred maximum number of bytes allowed for
# the serialized messages in a batch. A message larger than the preferred
# max bytes will result in a batch larger than preferred max bytes.
PreferredMaxBytes: 512 KB
The value is configured:
################################################################################
# SECTION: Orderer
################################################################################
Orderer: &OrdererDefaults
OrdererType: solo
Addresses:
#- orderer0.ordererorg:7050
- orderer0:7050
Kafka:
Brokers:
BatchTimeout: 2s
BatchSize:
MaxMessageCount: 10
AbsoluteMaxBytes: 98 MB
PreferredMaxBytes: 512 KB
Organizations:
The file is located in configtx.yaml, and it is defined in config.go.
// BatchSize contains configuration affecting the size of batches.
type BatchSize struct {
MaxMessageCount uint32 `yaml:"MaxMessageSize"`
AbsoluteMaxBytes uint32 `yaml:"AbsoluteMaxBytes"`
PreferredMaxBytes uint32 `yaml:"PreferredMaxBytes"`
}
The values are set according the configtx.yaml file above.
It's very difficult for me to understand GDT (Global Descriptor Table) in JOS (xv6-rev7)
For example
.word (((lim) >> 12) & 0xffff), ((base) & 0xffff);
Why shift right 12? Why AND 0xffff?
What do these number mean?
What does the formula mean?
Can anyone give me some resources or tutorials or hints?
Here, It's two parts of snippet code as following for my problem.
1st Part
0654 #define SEG_NULLASM \
0655 .word 0, 0; \
0656 .byte 0, 0, 0, 0
0657
0658 // The 0xC0 means the limit is in 4096−byte units
0659 // and (for executable segments) 32−bit mode.
0660 #define SEG_ASM(type,base,lim) \
0661 .word (((lim) >> 12) & 0xffff), ((base) & 0xffff); \
0662 .byte (((base) >> 16) & 0xff), (0x90 | (type)), \
0663 (0xC0 | (((lim) >> 28) & 0xf)), (((base) >> 24) & 0xff)
0664
0665 #define STA_X 0x8 // Executable segment
0666 #define STA_E 0x4 // Expand down (non−executable segments)
0667 #define STA_C 0x4 // Conforming code segment (executable only)
0668 #define STA_W 0x2 // Writeable (non−executable segments)
0669 #define STA_R 0x2 // Readable (executable segments)
0670 #define STA_A 0x1 // Accessed
2nd Part
8480 # Bootstrap GDT
8481 .p2align 2 # force 4 byte alignment
8482 gdt:
8483 SEG_NULLASM # null seg
8484 SEG_ASM(STA_X|STA_R, 0x0, 0xffffffff) # code seg
8485 SEG_ASM(STA_W, 0x0, 0xffffffff) # data seg
8486
8487 gdtdesc:
8488 .word (gdtdesc − gdt − 1) # sizeof(gdt) − 1
8489 .long gdt # address gdt
The complete part: http://pdos.csail.mit.edu/6.828/2012/xv6/xv6-rev7.pdf
Well, it isn't a real formula at all. Limit is shifted twelve bits to right, what's equivalent to division by 2^12, what is 4096, and that is granularity of GDT entry base, when G bit is set (in your code G bit is encoded in constants you use in your macro). Whenever address is to be accessed using correnspondig selector, only higher 20 bits are compared with limit and if they're greater, #GP is thrown. Also note that standard pages are 4KB in size, so any number greater than limit by less than 4 kilobytes is handled by page corresponding selector limit. Landing is there partly for suppressing compiler warnings about number overflow, as the operand 0xFFFF is maximal value for single word (16 bits).
Same applies for other shifts and AND, where in other expressions numbers can be shifted more to get another parts.
The structure of GDT descriptor sees above.
((lim) >> 12) & 0xffff) corresponding to Segment Limit(Bit 0-15). Shift right means minimal unit is 2^12 byte(granularity of GDT entry base); && 0xffff means we need the lower 16 bits of lim) >> 12, which fits to lowest part of 16 bits of GDT descriptor.
The rest of the 'formula' is the same.
here is a good material for learning GTD descriptor.