SimpleSSHD for Android

https://play.google.com/store/apps/details?id=org.galexander.sshd&hl=en

通过google play安装到手机,默认端口为2222,app手机启动后,需要点击启动按钮开启服务。app上会显示手机ip。

然后通过电脑ssh客户端连接,如 ssh 192.168.1.100 -p 2222,连接建立后会在app上显示随机分配的密码,再客户端输入后可以成功登陆了。可以在ssh文件目录下添加 authorized_keys文件,这样就不用每次输入了。

手机sd卡的目录为 /sdcard/,连接的普通用户是有读写访问权限的。可以使用rsync把手机相册的问题件同步到电脑上。rsync -e ‘ssh -p 2222’ -rtvpl 192.168.1.1:/sdcard/DCIM/ .

扩展:Asias使用rsync把手机图片视频原始文件同步到电脑,然后再压缩后回传到手机,这样大大减少了手机空间使用,而且压缩后的图片视频基本不影响查看。

Algorithm: Practical Set Reconciliation

《Practical Set Reconciliation》
Yaron Minsky Cornell University https://blog.janestreet.com/author/yminsky/
Ari Trachtenberg Boston University

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.456.7200&rep=rep1&type=pdf

def set_reconcile(src_seq, dst_seq):
    "Return required operations to mutate src_seq into dst_seq"
    src_set= set(src_seq) # no-op if already of type set
    dst_set= set(dst_seq) # ditto

    for item in src_set - dst_set:
        yield 'delete', item

    for item in dst_set - src_set:
        yield 'create', item

for i in set_reconcile([1,2,3,4], [2,3,4,5]):
    print i

$ python set_reconcile.py 
('delete', 1)
('create', 5)

Meet Casper

Casper was my colleague in Red Hat, we haven’t met each other for about 4 years. We knew same friends in Opensource communities before he join in Red Hat. He is working for Aliyun on system software area.

They want to cooperate with Universities, share their cool technology, provide guide and job position (intern or regular) for the students.

They investigated and used machine-learning in system software, one success usecase is key-value search, it’s quicker than hash table, but only for read most situation, that’s popular in their production environment.

scylla main.cc

main:
– cpu sse4.2 flag check
– init the uptime timer
– app template/config/options
– query_processor
– get storage_proxy
– get migration_manager
– http_context ctx (create)
– prometheus
– app.run_deprecated()
– parse args
– tcp_syncookies check
– seastar::async()
– dma read cfg
– apply logging settings
– verify rlimit(openfile)
– mem_per_shard 2 ** 32 ~= 1G
– check partitioner, Murmur3Partitioner is recommended
– cfg: assign setup parameters
– start prometheus API server
– set broadcast/broadcast_rpc
– client encryption
– create trace/snitch
– dns/api_address
– start API server(ctx.http_server)
– init storage service
– init per-shard core
– start engine
– init data dir
– init commitlog dir
– * init system keyspace
– * start gossip by init_ms_fd_gossiper()
– * start storage proxy
– start migration manager
– start query processor
– init batchlog manager
– init metrics?
– mini setup (sys ks)
– legacy schema migrate
– loading sstables
– setup sys ks
– start commitlog
– set storage/gossip/snitch/storage_proxy/load_sstable server to ctx
– init migration manager rpc verbs
– init storage proxy rpc verbs
– * start streaming service
– starting msg service
– start storage service
– start load broadcaster
– start cf/cache hit rate
– start native transport ( start (thrift) rpc)
– * set_server_done
– at_exit():
– repair_shutdown
– drain_on_shutdown
– compaction_manager stop

Key components
– storage proxy
– migration manager
– partitioner
– prometheus API server
– engine
– query processor
– streaming service
– thrift rpc
– compaction manager

[转发] 招聘 | 40K – 60K 招资深架构师、资深软件工程师

2017-05-11 CSDN企业招聘

北京涛思数据科技有限公司

涛思数据(TAOS Data)专注实时大数据的高效采集、存储、查询和分析。其自主开发的核心引擎写入数据的速度比普通数据库快五倍以上,查询速度快十倍以上。技术能广泛运用于物联网和金融行业,能大幅提升大数据系统的性能和容量,并降低运营成本。

2017年5月,涛思数据获得知名天使投资人薛蛮子和明势资本的投资。核心团队成员有多年在通讯设备、数据库、存储、大数据等领域的研发经验,创始人陶建辉曾成功创办“和信”与“快乐妈咪”两家高科技企业。

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