I thought there were some existing parametrics for the savings in mass fraction for a stage or a lander launched dry (versus wet), but apparently not. Is there anyone out there who whomp up a simple system in AutoCAD or Solidworks? Say 50,000 lbs of LOX/Hydrogen, launch acceleration 6 gees?
Category Archives: Technology and Society
Linux Problem
Can anyone figure out why /home is mounting read-only at boot?
Here’s my fstab:
# /etc/fstab
# Created by anaconda on Sat Apr 18 17:14:21 2015
#
# Accessible filesystems, by reference, are maintained under ‘/dev/disk’
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/fedora_new–host–5-root / ext4 defaults 1 1
UUID=058cc312-d471-41b9-a346-6ecf7dd2484b /boot ext4 defaults 1 2
#/dev/mapper/fedora_new–host–5-home /home ext4 defaults 1 2
/dev/mapper/fedora_new–host-home /home ext4 defaults 1 2
/dev/mapper/fedora_new–host–5-swap swap swap defaults 0 0
Note that /dev/mapper/fedora_new–host–5-root is an SSD (as is boot), and /dev/mapper/fedora_new–host-home is a physical hard drive.
And here’s /proc/mounts:
sysfs /sys sysfs rw,seclabel,nosuid,nodev,noexec,relatime 0 0
proc /proc proc rw,nosuid,nodev,noexec,relatime 0 0
devtmpfs /dev devtmpfs rw,seclabel,nosuid,size=7787916k,nr_inodes=1946979,mode=755 0 0
securityfs /sys/kernel/security securityfs rw,nosuid,nodev,noexec,relatime 0 0
tmpfs /dev/shm tmpfs rw,seclabel,nosuid,nodev 0 0
devpts /dev/pts devpts rw,seclabel,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000 0 0
tmpfs /run tmpfs rw,seclabel,nosuid,nodev,mode=755 0 0
tmpfs /sys/fs/cgroup tmpfs ro,seclabel,nosuid,nodev,noexec,mode=755 0 0
cgroup /sys/fs/cgroup/systemd cgroup rw,nosuid,nodev,noexec,relatime,xattr,release_agent=/usr/lib/systemd/systemd-cgroups-agent,name=systemd 0 0
pstore /sys/fs/pstore pstore rw,seclabel,nosuid,nodev,noexec,relatime 0 0
cgroup /sys/fs/cgroup/blkio cgroup rw,nosuid,nodev,noexec,relatime,blkio 0 0
cgroup /sys/fs/cgroup/net_cls,net_prio cgroup rw,nosuid,nodev,noexec,relatime,net_cls,net_prio 0 0
cgroup /sys/fs/cgroup/hugetlb cgroup rw,nosuid,nodev,noexec,relatime,hugetlb 0 0
cgroup /sys/fs/cgroup/memory cgroup rw,nosuid,nodev,noexec,relatime,memory 0 0
cgroup /sys/fs/cgroup/perf_event cgroup rw,nosuid,nodev,noexec,relatime,perf_event 0 0
cgroup /sys/fs/cgroup/cpu,cpuacct cgroup rw,nosuid,nodev,noexec,relatime,cpu,cpuacct 0 0
cgroup /sys/fs/cgroup/cpuset cgroup rw,nosuid,nodev,noexec,relatime,cpuset 0 0
cgroup /sys/fs/cgroup/freezer cgroup rw,nosuid,nodev,noexec,relatime,freezer 0 0
cgroup /sys/fs/cgroup/devices cgroup rw,nosuid,nodev,noexec,relatime,devices 0 0
configfs /sys/kernel/config configfs rw,relatime 0 0
/dev/mapper/fedora_new–host–5-root / ext4 rw,seclabel,relatime,data=ordered 0 0
selinuxfs /sys/fs/selinux selinuxfs rw,relatime 0 0
systemd-1 /proc/sys/fs/binfmt_misc autofs rw,relatime,fd=24,pgrp=1,timeout=300,minproto=5,maxproto=5,direct 0 0
tmpfs /tmp tmpfs rw,seclabel 0 0
debugfs /sys/kernel/debug debugfs rw,seclabel,relatime 0 0
hugetlbfs /dev/hugepages hugetlbfs rw,seclabel,relatime 0 0
mqueue /dev/mqueue mqueue rw,seclabel,relatime 0 0
nfsd /proc/fs/nfsd nfsd rw,relatime 0 0
/dev/sdb1 /boot ext4 rw,seclabel,relatime,data=ordered 0 0
/dev/mapper/fedora_new–host-home /home ext4 ro,seclabel,relatime,data=ordered 0 0
sunrpc /var/lib/nfs/rpc_pipefs rpc_pipefs rw,relatime 0 0
tmpfs /run/user/42 tmpfs rw,seclabel,nosuid,nodev,relatime,size=1559960k,mode=700,uid=42,gid=42 0 0
tmpfs /run/user/1000 tmpfs rw,seclabel,nosuid,nodev,relatime,size=1559960k,mode=700,uid=1000,gid=1000 0 0
gvfsd-fuse /run/user/1000/gvfs fuse.gvfsd-fuse rw,nosuid,nodev,relatime,user_id=1000,group_id=1000 0 0
fusectl /sys/fs/fuse/connections fusectl rw,relatime 0 0
binfmt_misc /proc/sys/fs/binfmt_misc binfmt_misc rw,relatime 0 0
[Update a while later]
OK, clearly the disk is getting corrupted. I put in a file check option in the fstab, and it (temporarily) mounted it read-write at boot, but after working a while it became remounted read-only.
Any suggestions?
[Update a while later]
I had a spare 2T drive that I hooked up, and made it /home at boot (it was an old original, and the new drive was actually backup of it, so it had a lot of the data on it already). It’s working fine so far, except that when I copied my Gnome user configuration data over and rebooted, it decided that I wanted to have a Spanish desktop. I’ve changed the system settings to en_US, and even ‘localectl status’ give me:
System Locale: LANG=en_US
VC Keymap: us
X11 Layout: us
I can’t figure out where in the configuration files it’s getting the idea that I want to compute en Espanol, but while I can stumble along in it, it’s quite annoying.
[Wednesday-morning update]
OK, I determined that the language is changed in Gnome in “Settings,” but in the Spanish interface, that gets translated into “Configuracion,” so I was looking in the wrong place. So, now all is well, as far as I can tell. And as of this morning both the old and the new drive remain read/write. So still not sure what the problem was, but it seems to be a lot better now.
[Update a while later]
Wow. That drive had been causing problems I hadn’t even realized. My system had been running like molasses, with lots of runaway processes (like in Chrome). That’s completely disappeared. It’s like greased lightning now, even with several instances and many dozens of tabs open in Firefox.
Meth
It’s not an argument for drug prohibition; it’s a demonstration and consequence of the failure of drug prohibition.
Hillary’s Server
It was even less secure than previously thought.
This is my shocked face.
As someone noted on Twitter, this is the equivalent of leaving a new Mercedes out on the street with the key taped to the outside of the windshield.
Lyndon Johnson’s Daily Brief
I’ve been looking forward to this. Some formerly classified documents from the Apollo era have emerged.
Hoplophobic Professors
I think they should be shunned and punished for being the bigots that they are.
Gary Gygax
Thoughts on his suggested reading list:
Ideological diversity in science fiction and fantasy was a given in the seventies. We are hopelessly homogenistic in comparison to them.
The program of political correctness of the past several decades has made even writers like Ray Bradbury and C. L. Moore all but unreadable to an entire generation. The conditioning is so strong, some people have almost physical reactions to the older stories now.
All part of the reason that I don’t read anywhere near as much SF as I did as a kid.
Hillary’s Server
What the FBI is up to. And fresh evidence continues to undermine her email defense.
And, no Barack, it’s actually kind of stupid to think that this wasn’t a major breach of security. And it’s corrupt to weigh in with your opinion on an ongoing investigation as you did here (and with the “not a smidgen of evidence” about the IRS). Now the FBI has to operate under the burden of knowledge that you won’t be happy if they dispute the president.
How Scientists Fool Themselves
…and how they can stop.
Global Warming Scare Tactics
…environmental groups have known since 2000 that efforts to link climate change to natural disasters could backfire, after researchers at the Frameworks Institute studied public attitudes for its report “How to Talk About Global Warming.” Messages focused on extreme weather events, they found, made many Americans more likely to view climate change as an act of God — something to be weathered, not prevented.
Some people, the report noted, “are likely to buy an SUV to help them through the erratic weather to come” for example, rather than support fuel-efficiency standards.
Since then, evidence that a fear-based approach backfires has grown stronger. A frequently cited 2009 study in the journal Science Communication summed up the scholarly consensus. “Although shocking, catastrophic, and large-scale representations of the impacts of climate change may well act as an initial hook for people’s attention and concern,” the researchers wrote, “they clearly do not motivate a sense of personal engagement with the issue and indeed may act to trigger barriers to engagement such as denial.” In a controlled laboratory experiment published in Psychological Science in 2010, researchers were able to use “dire messages” about global warming to increase skepticism about the problem.
Many climate advocates ignore these findings, arguing that they have an obligation to convey the alarming facts.
But claims linking the latest blizzard, drought or hurricane to global warming simply can’t be supported by the science. Our warming world is, according to the United Nations Intergovernmental Panel on Climate Change, increasing heat waves and intense precipitation in some places, and is likely to bring more extreme weather in the future. But the panel also said there is little evidence that this warming is increasing the loss of life or the economic costs of natural disasters. “Economic growth, including greater concentrations of people and wealth in periled areas and rising insurance penetration,” the climate panel noted, “is the most important driver of increasing losses.”
People like the Bills McKibben and Nye look like fools when they seize on every weather event to evangelize their religion.