我的意思是收到从第10字节开始的60个字节就停止，
为什么我的运行结果是从第10字节开始的所有数据都收下来
了之后服务器才对我发的ABOR有响应呢？
服务器是ser-u4.0不可能不支持断点续传的呀。

我的程序是这样的：
from ftplib import FTP

def cb( s ):
    global f, a
    a = a + len( s )
    print 'cb( %s )' % s
    if a >=60:
        print 'SendAbor!!'
        f.abort()

a = 0
print '----------------------------'

host    = '202.120.113.31'
port    = 22
login   = 'leojay'
passwd  = 'leojayhaha'

f = FTP()
print "Connecting to '%s%s'..." % (host,port)
print 'f.connect(host,port):', f.connect(host,port)

print 'Logging in as %s...' % login
print 'f.login( login, passwd ): ', f.login( login, passwd )

print 'f.retrbinary: ', f.retrbinary( 'RETR /n.txt', cb, 20, 10 )
print 'f.quit(): ', f.quit()

print 'a =', a

服务器上的文件n.txt是这样的：
Name: Rich 7 [Game]
License:Trade
Language:Simplified Chinese
Means:First
Enclosure:CloneCD Image & Alcohol Image (2CD)
Official WebSite:http://www.unistar.net.cn/
Supply:by Sms2000[LJF]
运行的输出是这样的：
----------------------------
Connecting to '202.120.113.3122'...
f.connect(host,port): 220 Serv-U FTP Server v4.0 for WinSock ready...
Logging in as leojay...
f.login( login, passwd ):  230 User logged in, proceed.
f.retrbinary:  cb(  7 [Game]

License:T )
cb( rade

Language:Simpl )
cb( ified Chinese

Means )
SendAbor!!
cb( :First

Enclosure:Cl )
SendAbor!!
cb( oneCD Image & Alcoho )
SendAbor!!
cb( l Image (2CD)

Offic )
SendAbor!!
cb( ial WebSite:http://w )
SendAbor!!
cb( ww.unistar.net.cn/

 )
SendAbor!!
cb( Supply:by Sms2000[LJ )
SendAbor!!
cb( F] )
SendAbor!!
226 ABOR command successful.
f.quit():  221 Goodbye!
a = 182
显然是发了好几次ABOR给服务器，但都没结果的嘛
哪位大哥知道是怎么回事吗？谢谢了