在利用Keil C51编程时，发现程序逻辑上没有错误，但在连接时却出现了错误，如下：

*** ERROR L107: ADDRESS SPACE OVERFLOW

SPACE:   DATA

SEGMENT: ?DT?GMNS_3V4

LENGTH: 0014H

*** ERROR L105: PUBLIC REFERS TO IGNORED SEGMENT

SYMBOL: RECEIVE_TIMER

SEGMENT: ?DT?GMNS_3V4

*** ERROR L105: PUBLIC REFERS TO IGNORED SEGMENT

SYMBOL: DUAL_REC_BUF

SEGMENT: ?DT?GMNS_3V4

*** ERROR L105: PUBLIC REFERS TO IGNORED SEGMENT

SYMBOL: LAST_SEND_TIME_COUNT

SEGMENT: ?DT?GMNS_3V4

*** ERROR L105: PUBLIC REFERS TO IGNORED SEGMENT

SYMBOL: POW_STATUS

SEGMENT: ?DT?GMNS_3V4

*** ERROR L105: PUBLIC REFERS TO IGNORED SEGMENT

SYMBOL: POW_STATE

SEGMENT: ?DT?GMNS_3V4

*** ERROR L105: PUBLIC REFERS TO IGNORED SEGMENT

SYMBOL: GROUP_TEST

SEGMENT: ?DT?GMNS_3V4

*** ERROR L105: PUBLIC REFERS TO IGNORED SEGMENT

SYMBOL: S_COUNT_P

SEGMENT: ?DT?GMNS_3V4

*** ERROR L105: PUBLIC REFERS TO IGNORED SEGMENT

SYMBOL: R_COUNT_P

SEGMENT: ?DT?GMNS_3V4

*** ERROR L105: PUBLIC REFERS TO IGNORED SEGMENT

SYMBOL: RING_JUDGE_STATEB1

SEGMENT: ?DT?GMNS_3V4

*** ERROR L105: PUBLIC REFERS TO IGNORED SEGMENT

SYMBOL: RING_JUDGE_STATEB0

SEGMENT: ?DT?GMNS_3V4

*** ERROR L105: PUBLIC REFERS TO IGNORED SEGMENT

SYMBOL: YAOXIN_CHECK_STATUS4

SEGMENT: ?DT?GMNS_3V4

*** ERROR L105: PUBLIC REFERS TO IGNORED SEGMENT

SYMBOL: YAOXIN_CHECK_STATUS3

SEGMENT: ?DT?GMNS_3V4

*** ERROR L105: PUBLIC REFERS TO IGNORED SEGMENT

SYMBOL: YAOXIN_CHECK_STATUS2

SEGMENT: ?DT?GMNS_3V4

*** ERROR L105: PUBLIC REFERS TO IGNORED SEGMENT

SYMBOL: YAOXIN_CHECK_STATUS1

SEGMENT: ?DT?GMNS_3V4

*** ERROR L105: PUBLIC REFERS TO IGNORED SEGMENT

SYMBOL: YAOXIN_CHECK_STATUS0

SEGMENT: ?DT?GMNS_3V4

*** ERROR L105: PUBLIC REFERS TO IGNORED SEGMENT

SYMBOL: YAO_XIN_COUNT

SEGMENT: ?DT?GMNS_3V4

出现以上错误的原因主要是第一个原因，第一个原因导致了它下面所有错误，第一个原因是：

ERROR L107: ADDRESS SPACE OVERFLOW

SPACE:   DATA

SEGMENT: ?DT?GMNS_3V4

LENGTH: 0014H

说明data空间已经不够用，原因是你可能有好多函数，而函数内部的局部变量又没有定义其空间，这种情况下，系统会将变量分配到你在Otions for Target 对话框里的设置的空间。如果你在下图所示中的 Memory Model 里设置成 Small:variables in DATA,则DATA空间很快便用完，导致data空间不够用。解决的办法有两种，一是通过更改Memory Model设置，可以设置成pdata或xdata，以便有足够大的空间，但这又带来新的问题，程序运行速度减慢，而且code代码也会加大，因为如果一个局部变量被存放在了xdata空间，汇编语言访问xdata空间的代码大小要比访问data空间的代码大，变量一旦很多，程序的代码也会逐渐增大；二是根据自己的要求设置变量的空间。所以这涉及到代码优化的问题，遇到具体问题时，在运行速度和代码大小之间取得适合自己的情况。